Python Programming Puzzles - Exercises, Practice, Solution

Python Programming Puzzles [100 exercises with solution]

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1. Check Nineteen and Five Occurrences

Write a Python program to find a list of integers with exactly two occurrences of nineteen and at least three occurrences of five. Return True otherwise False.
Input:
[19, 19, 15, 5, 3, 5, 5, 2]
Output:
True
Input:
[19, 15, 15, 5, 3, 3, 5, 2]
Output:
False
Input:
[19, 19, 5, 5, 5, 5, 5]
Output:
True
Click me to see the sample solution

2. Fifth Element and List Length Check

Write a Python program that accepts a list of integers and calculates the length and the fifth element. Return true if the length of the list is 8 and the fifth element occurs thrice in the said list.
Input:
[19, 19, 15, 5, 5, 5, 1, 2]
Output:
True
Input:
[19, 15, 5, 7, 5, 5, 2]
Output:
False
Input:
[11, 12, 14, 13, 14, 13, 15, 14]
Output:
True
Input:
[19, 15, 11, 7, 5, 6, 2]
Output:
False
Click me to see the sample solution

3. Integer Greater Than 444^444 and Mod 34

Write a Python program that accepts an integer and determines whether it is greater than 4^4 and which is 4 mod 34.
Input:
922
Output:
True
Input:
914
Output:
False
Input:
854
Output:
True
Input:
854
Output:
True
Click me to see the sample solution

4. Stone Piles Distribution

We are making n stone piles! The first pile has n stones. If n is even, then all piles have an even number of stones. If n is odd, all piles have an odd number of stones. Each pile must more stones than the previous pile but as few as possible. Write a Python program to find the number of stones in each pile.
Input: 2
Output:
[2, 4]
Input: 10
Output:
[10, 12, 14, 16, 18, 20, 22, 24, 26, 28]
Input: 3
Output:
[3, 5, 7]
Input: 17
Output:
[17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49]
Click me to see the sample solution

5. Substring in String List Check

Write a Python program to check the n^th-1 string is a proper substring of the n^th string in a given list of strings.
Input:
['a', 'abb', 'sfs', 'oo', 'de', 'sfde']
Output:
True
Input:
['a', 'abb', 'sfs', 'oo', 'ee', 'sfde']
Output:
False
Input:
['a', 'abb', 'sad', 'ooaaesdfe', 'sfsdfde', 'sfsd', 'sfsdf', 'qwrew']
Output:
False
Input:
['a', 'abb', 'sad', 'ooaaesdfe', 'sfsdfde', 'sfsd', 'sfsdf', 'qwsfsdfrew']
Output:
True
Click me to see the sample solution

6. List Integers Differ by Ten

Write a Python program to test a list of one hundred integers between 0 and 999, which all differ by ten from one another. Return True otherwise False.
Input:
[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990]
Output:
True
Input:
[0, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480, 500, 520, 540, 560, 580, 600, 620, 640, 660, 680, 700, 720, 740, 760, 780, 800, 820, 840, 860, 880, 900, 920, 940, 960, 980]
Output:
False
Click me to see the sample solution

7. Sum of First i Equals i

Write a Python program to check a given list of integers where the sum of the first i integers is i.
Input:
[0, 1, 2, 3, 4, 5]
Output:
False
Input:
[1, 1, 1, 1, 1, 1]
Output:
True
Input:
[2, 2, 2, 2, 2]
Output:
False
Click me to see the sample solution

8. Split String into Words and Separators

Write a Python program to split a string of words separated by commas and spaces into two lists, words and separators.
Input: W3resource Python, Exercises.
Output:
[['W3resource', 'Python', 'Exercises.'], [' ', ', ']]
Input: The dance, held in the school gym, ended at midnight.
Output:
[['The', 'dance', 'held', 'in', 'the', 'school', 'gym', 'ended', 'at', 'midnight.'], [' ', ', ', ' ', ' ', ' ', ' ', ', ', ' ', ' ']]
Input: The colors in my studyroom are blue, green, and yellow.
Output:
[['The', 'colors', 'in', 'my', 'studyroom', 'are', 'blue', 'green', 'and', 'yellow.'], [' ', ' ', ' ', ' ', ' ', ' ', ', ', ', ', ' ']]
Click me to see the sample solution

9. Four Distinct Values Non-Consecutive

10. Split Matched Parentheses Groups

Given a string consisting of whitespace and groups of matched parentheses, write a Python program to split it into groups of perfectly matched parentheses without any whitespace.
Input:
( ()) ((()()())) (()) ()
Output:
['(())', '((()()()))', '(())', '()']
Input:
() (( ( )() ( )) ) ( ())
Output:
['()', '((()()()))', '(())']
Click me to see the sample solution

11. Indices Below Threshold

Write a Python program to find the indexes of numbers in a given list below a given threshold.
Original list:
[0, 12, 45, 3, 4923, 322, 105, 29, 15, 39, 55]
Threshold: 100
Check the indexes of numbers of the said list below the given threshold:
[0, 1, 2, 3, 7, 8, 9, 10]
Original list:
[0, 12, 4, 3, 49, 9, 1, 5, 3]
Threshold: 10
Check the indexes of numbers of the said list below the given threshold:
[0, 2, 3, 5, 6, 7, 8]
Click me to see the sample solution

12. Check Palindromes in List

Write a Python program to check whether the given strings are palindromes or not. Return True otherwise False.
Input:
['palindrome', 'madamimadam', '', 'foo', 'eyes']
Output:
[False, True, True, False, False]
Click me to see the sample solution

13. Find Strings with Prefix

Write a Python program to find strings in a given list starting with a given prefix.
Input:
[( ca,('cat', 'car', 'fear', 'center'))]
Output:
['cat', 'car']
Input:
[(do,('cat', 'dog', 'shatter', 'donut', 'at', 'todo'))]
Output:
['dog', 'donut']
Click me to see the sample solution

14. Length of Strings in List

Write a Python program to find the length of a given list of non-empty strings.
Input:
['cat', 'car', 'fear', 'center']
Output:
[3, 3, 4, 6]
Input:
['cat', 'dog', 'shatter', 'donut', 'at', 'todo', '']
Output:
[3, 3, 7, 5, 2, 4, 0]
Click me to see the sample solution

15. Longest String in List

Write a Python program to find the longest string in a given list of strings.
Input:
['cat', 'car', 'fear', 'center']
Output:
center
Input:
['cat', 'dog', 'shatter', 'donut', 'at', 'todo', '']
Output:
shatter
Click me to see the sample solution

16. Find Strings with Substring

Write a Python program to find strings in a given list containing a given substring.
Input:
[(ca,('cat', 'car', 'fear', 'center'))]
Output:
['cat', 'car']
Input:
[(o,('cat', 'dog', 'shatter', 'donut', 'at', 'todo', ''))]
Output:
['dog', 'donut', 'todo']
Input:
[(oe,('cat', 'dog', 'shatter', 'donut', 'at', 'todo', ''))]
Output:
[]
Click me to see the sample solution

17. Create String of Non-Negatives to n

Write a Python program to create a string consisting of non-negative integers up to n inclusive.
Input:
4
Output:
0 1 2 3 4
Input:
15
Output:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Click me to see the sample solution

18. Target Indices in Uneven Matrix

An irregular/uneven matrix, or ragged matrix, is a matrix that has a different number of elements in each row. Ragged matrices are not used in linear algebra, since standard matrix transformations cannot be performed on them, but they are useful as arrays in computing.
Write a Python program to find the indices of all occurrences of target in the uneven matrix.
Input:
[([1, 3, 2, 32, 19], [19, 2, 48, 19], [], [9, 35, 4], [3, 19]),19]
Output:
[[0, 4], [1, 0], [1, 3], [4, 1]]
Input:
[([1, 2, 3, 2], [], [7, 9, 2, 1, 4]),2]
Output:
[[0, 1], [0, 3], [2, 2]]
Click me to see the sample solution

19. Split String on Space or Comma

Write a Python program to split a given string (s) into strings if there is a space in s, otherwise split on commas if there is a comma, otherwise return the list of lowercase letters in odd order (order of a = 0, b = 1, etc.).
Input:
a b c d
Split the said string into strings if there is a space in the string,
otherwise split on commas if there is a comma,
Output:
['a', 'b', 'c', 'd']
Input:
a,b,c,d
Split the said string into strings if there is a space in the string,
otherwise split on commas if there is a comma,
Output:
['a', 'b', 'c', 'd']
Input:
abcd
Split the said string into strings if there is a space in the string,
otherwise split on commas if there is a comma,
Output:
['b', 'd']
Click me to see the sample solution

20. Determine Monotonic Direction

Write a Python program to determine the direction ('increasing' or 'decreasing') of monotonic sequence numbers.
Input:
[1, 2, 3, 4, 5, 6]
Output:
Increasing.
Input:
[6, 5, 4, 3, 2, 1]
Output:
Decreasing.
Input:
[19, 19, 5, 5, 5, 5, 5]
Output:
Not a monotonic sequence!
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21. Isolated Last Character Check

Write a Python program to check, for each string in a given list, whether the last character is an isolated letter or not. Return True otherwise False.
Input:
['cat', 'car', 'fear', 'center']
Output:
[False, False, False, False]
Input:
['ca t', 'car', 'fea r', 'cente r']
Output:
[True, False, True, True]
Click me to see the sample solution

22. Sum of ASCII for Uppercase Letters

Write a Python program to compute the sum of the ASCII values of the upper-case characters in a given string.
Input:
PytHon ExerciSEs
Output:
373
Input:
JavaScript
Output:
157
Click me to see the sample solution

23. Indices of Drops in List

Write a Python program to find the indices at which the numbers in the list drop.
NOTE: You can detect multiple drops just by checking if nums[i] < nums[i-1]
Input:
[0, -1, 3, 8, 5, 9, 8, 14, 2, 4, 3, -10, 10, 17, 41, 22, -4, -4, -15, 0]
Output:
[1, 4, 6, 8, 10, 11, 15, 16, 18]
Input:
[6, 5, 4, 3, 2, 1]
Output:
[1, 2, 3, 4, 5]
Input:
[1, 19, 5, 15, 5, 25, 5]
Output:
[0, 2, 4, 6]
Click me to see the sample solution

24. Max of First i Elements

Write a Python program to create a list whose i^th element is the maximum of the first i elements from an input list.
Input:
[0, -1, 3, 8, 5, 9, 8, 14, 2, 4, 3, -10, 10, 17, 41, 22, -4, -4, -15, 0]
Output:
[0, 0, 3, 8, 8, 9, 9, 14, 14, 14, 14, 14, 14, 17, 41, 41, 41, 41, 41, 41]
Input:
[6, 5, 4, 3, 2, 1]
Output:
[6, 6, 6, 6, 6, 6]
Input:
[1, 19, 5, 15, 5, 25, 5]
Output:
[1, 19, 19, 19, 19, 25, 25]
Click me to see the sample solution

25. XOR of Binary Strings

Write a Python program to find the XOR of two given strings interpreted as binary numbers.
Input:
['0001', '1011']
Output:
0b1010
Input:
['100011101100001', '100101100101110']
Output:
0b110001001111
Click me to see the sample solution

26. Largest Number with Commas/Periods

Write a Python program to find the largest number where commas or periods are decimal points.
Input:
['100', '102,1', '101.1']
Output:
102.1
Click me to see the sample solution

27. Minimize Mean Squared Deviation

Write a Python program to find x that minimizes the mean squared deviation from a given list of numbers.
Input:
[4, -5, 17, -9, 14, 108, -9]
Output:
17.142857142857142
Input:
[12, -2, 14, 3, -15, 10, -45, 3, 30]
Output:
1.1111111111111112
Click me to see the sample solution

28. String with Most Unique Characters

Write a Python program to select a string from a given list of strings with the most unique characters.
Input:
['cat', 'catatatatctsa', 'abcdefhijklmnop', '124259239185125', '', 'foo', 'unique']
Output:
abcdefhijklmnop
Input:
['Green', 'Red', 'Orange', 'Yellow', '', 'White']
Output:
Orange
Click me to see the sample solution

29. Indices of Numbers Summing to Zero

Write a Python program to find the indices of two numbers that sum to 0 in a given list of numbers.
Input:
[1, -4, 6, 7, 4]
Output:
[4, 1]
Input:
[1232, -20352, 12547, 12440, 741, 341, 525, 20352, 91, 20]
Output:
[1, 7]
Click me to see the sample solution

30. List with Fewer Total Characters

Write a Python program to find a list of strings that have fewer total characters (including repetitions).
Input:
[['this', 'list', 'is', 'narrow'], ['I', 'am', 'shorter but wider']]
Output:
['this', 'list', 'is', 'narrow']
Input:
[['Red', 'Black', 'Pink'], ['Green', 'Red', 'White']]
Output:
['Red', 'Black', 'Pink']
Click me to see the sample solution

31. Triangle Coordinates Finder

Write a Python program to find the coordinates of a triangle with given side lengths.
Input:
[3, 4, 5]
Output:
[[0.0, 0.0], [3, 0.0], [3.0, 4.0]]
Input:
[5, 6, 7]
Output:
[[0.0, 0.0], [5, 0.0], [3.8, 5.878775382679628]]
Click me to see the sample solution

32. Rescale List to [0,1]

Write a Python program to rescale and shift numbers in a given list, so that they cover the range [0, 1].
Input:
[18.5, 17.0, 18.0, 19.0, 18.0]
Output:
[0.75, 0.0, 0.5, 1.0, 0.5]
Input:
[13.0, 17.0, 17.0, 15.5, 2.94]
Output:
[0.7155049786628734, 1.0, 1.0, 0.8933143669985776, 0.0]
Click me to see the sample solution

33. Uppercase Vowel Positions

Write a Python program to find the positions of all uppercase vowels (not counting Y) in even indices of a given string.
Input: w3rEsOUrcE
Output:
[6]
Input: AEIOUYW
Output:
[0, 2, 4]
Click me to see the sample solution

34. Sum of Numbers with 2+ Digits

Write a Python program to find the sum of the numbers in a given list among the first k with more than 2 digits.
Input: [4, 5, 17, 9, 14, 108, -9, 12, 76]
Value of K: 4
Output:
0
Input: [4, 5, 17, 9, 14, 108, -9, 12, 76]
Value of K: 6
Output:
108
Input: [114, 215, -117, 119, 14, 108, -9, 12, 76]
Value of K: 5
Output:
331
Input: [114, 215, -117, 119, 14, 108, -9, 12, 76]
Value of K: 1
Output:
114
Click me to see the sample solution

35. Product of Odd Digits

Write a Python program to compute the product of the odd digits in a given number, or 0 if there aren't any.
Input: 123456789
Output:
945
Input: 2468
Output:
0
Input: 13579
Output:
945
Click me to see the sample solution

36. Find Largest K Numbers

Write a Python program to find the largest k numbers from a given list of numbers.
Input: [1, 2, 3, 4, 5, 5, 3, 6, 2]
Output:
[6]
Input: [1, 2, 3, 4, 5, 5, 3, 6, 2]
Output:
[6, 5]
Input: [1, 2, 3, 4, 5, 5, 3, 6, 2]
Output:
[6, 5, 5]
Input: [1, 2, 3, 4, 5, 5, 3, 6, 2]
Output:
[6, 5, 5, 4]
Input: [1, 2, 3, 4, 5, 5, 3, 6, 2]
Output:
[6, 5, 5, 4, 3]
Click me to see the sample solution

37. Largest Proper Divisor

Write a Python program to find the largest integer divisor of a number n that is less than n.
Input: 18
Output:
9
Input: 100
Output:
50
Input: 102
Output:
51
Input: 500
Output:
250
Input: 1000
Output:
500
Input: 6500
Output:
3250
Click me to see the sample solution

38. Sort by Digit Sum

Write a Python program to sort the numbers in a given list by the sum of their digits.
Input: [10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
Output:
[10, 11, 20, 12, 13, 14, 15, 16, 17, 18, 19]
Input: [23, 2, 9, 34, 8, 9, 10, 74]
Output:
[10, 2, 23, 34, 8, 9, 9, 74]
Click me to see the sample solution

39. Zero-Sum Triples Finder

Write a Python program to determine which triples sum to zero from a given list of lists.
Input: [[1343532, -2920635, 332], [-27, 18, 9], [4, 0, -4], [2, 2, 2], [-20, 16, 4]]
Output:
[False, True, True, False, True]
Input: [[1, 2, -3], [-4, 0, 4], [0, 1, -5], [1, 1, 1], [-2, 4, -1]]
Output:
[True, True, False, False, False]
Click me to see the sample solution

40. Flip Case and Shift Vowels

Write a Python program to find strings that, when case is flipped, give a target where vowels are replaced by characters two later.
Input: Python
Output:
pYTHQN
Input: aeiou
Output:
CGKQW
Input: Hello, world!
Output:
hGLLQ, WQRLD!
Input: AEIOU
Output:
cgkqw
Click me to see the sample solution

41. Sort Numbers from Words

Write a Python program to sort numbers based on strings.
Input: six one four one two three
Output:
one two three four six
Input: six one four three two nine eight
Output:
one two three four six eight nine
Input: nine eight seven six five four three two one
Output:
one two three four five six seven eight nine
Click me to see the sample solution

42. Distinct Characters in String

Write a Python program to find the set of distinct characters in a given string, ignoring case.
Input: HELLO
Output:
['h', 'o', 'l', 'e']
Input: HelLo
Output:
['h', 'o', 'l', 'e']
Input: Ignoring case
Output:
['s', 'n', 'c', 'o', 'e', 'i', 'r', 'g', 'a', ' ']
Click me to see the sample solution

43. Words with N Consonants

Write a Python program to find all words in a given string with n consonants.
Input: this is our time
Output:
Number of consonants: 3
Words in the said string with 3 consonants:
['this']
Number of consonants: 2
Words in the said string with 2 consonants:
['time']
Number of consonants: 1
Words in the said string with 1 consonants:
['is', 'our']
Click me to see the sample solution

44. Hexadecimal Prime Characters

Write a Python program to find which characters of a hexadecimal number correspond to prime numbers.
Input: 123ABCD
Output:
[False, True, True, False, True, False, True]
Input: 123456
Output:
[False, True, True, False, True, False]
Input: FACE
Output:
[False, False, False, False]
Click me to see the sample solution

45. Find Even Palindromes

Write a Python program to find all even palindromes up to n.
Output:
Even palindromes up to 50 -
[0, 2, 4, 6, 8, 22, 44]
Even palindromes up to 100 -
[0, 2, 4, 6, 8, 22, 44, 66, 88]
Even palindromes up to 500 -
[0, 2, 4, 6, 8, 22, 44, 66, 88, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494]
Even palindromes up to 2000 -
[0, 2, 4, 6, 8, 22, 44, 66, 88, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494, 606, 616, 626, 636, 646, 656, 666, 676, 686, 696, 808, 818, 828, 838, 848, 858, 868, 878, 888, 898]
Click me to see the sample solution

46. Minimum Even Value and Index

Given an array of numbers representing a branch on a binary tree, write a Python program to find the minimum even value and its index. In the case of a tie, return the smallest index. If there are no even numbers, the answer is [].
Input:
[1, 9, 4, 6, 10, 11, 14, 8]
Output:
Minimum even value and its index of the said array of numbers:
[4, 2]
Input:
[1, 7, 4, 4, 9, 2]
Output:
Minimum even value and its index of the said array of numbers:
[2, 5]
Input:
[1, 7, 7, 5, 9]
Output:
Minimum even value and its index of the said array of numbers:
[]
Click me to see the sample solution

47. Filter by Sum of Digits

Write a Python program to filter for numbers in a given list whose sum of digits is > 0, where the first digit can be negative.
Input:
[11, -6, -103, -200]
Output:
[11, -103]
Input:
[1, 7, -4, 4, -9, 2]
Output:
[1, 7, 4, 2]
Input:
[10, -11, -71, -13, 14, -32]
Output:
[10, -13, 14]
Click me to see the sample solution

48. Find Non-Increasing Indices

Write a Python program to find the indices of two entries that show that the list is not in increasing order. If there are no violations (they are increasing), return an empty list.
Input:
[1, 2, 3, 0, 4, 5, 6]
Output:
[2, 3]
Input:
[1, 2, 3, 4, 5, 6]
Output:
[]
Input:
[1, 2, 3, 4, 6, 5, 7]
Output:
[4, 5]
Input:
[-3, -2, -3, 0, 2, 3, 4]
Output:
[1, 2]
Click me to see the sample solution

49. H-Index Finder

Write a Python program to find the h-index, the largest positive number h such that h occurs in the sequence at least h times. If there is no such positive number return h = -1.
Input:
[1, 2, 2, 3, 3, 4, 4, 4, 4]
Output:
4
Input:
[1, 2, 2, 3, 4, 5, 6]
Output:
2
Input:
[3, 1, 4, 17, 5, 17, 2, 1, 41, 32, 2, 5, 5, 5, 5]
Output:
5
Click me to see the sample solution

50. Sort Even-Length Words

Write a Python program to find even-length words from a given list of words and sort them by length.
Original list of words:
['Red', 'Black', 'White', 'Green', 'Pink', 'Orange']
Find the even-length words and sort them by length in the said list of words:
['Pink', 'Orange']
Original list of words:
['The', 'worm', 'ate', 'a', 'bird', 'imagine', 'that', '!', 'Absurd', '!!']
Find the even-length words and sort them by length in the said list of words:
['!!', 'bird', 'that', 'worm', 'Absurd']
Click me to see the sample solution

51. Product of Units Digits

Write a Python program to find the product of the units digits in the numbers in a given list.
Input: 10
Output:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
Input: 15
Output:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
Input: 50
Output:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269, 2178309, 3524578, 5702887, 9227465, 14930352, 24157817, 39088169, 63245986, 102334155, 165580141, 267914296, 433494437, 701408733, 1134903170, 1836311903, 2971215073, 4807526976, 7778742049, 12586269025]
Click me to see the sample solution

52. Reverse Case or Reverse Strings

Write a Python program to reverse the case of all strings. For those strings, which contain no letters, reverse the strings.
Original list:
['cat', 'catatatatctsa', 'abcdefhijklmnop', '124259239185125', '', 'foo', 'unique']
Reverse the case of all strings. For those strings which contain no letters, reverse the strings:
['CAT', 'CATATATATCTSA', 'ABCDEFHIJKLMNOP', '521581932952421', '', 'FOO', 'UNIQUE']
Original list:
['Green', 'Red', 'Orange', 'Yellow', '', 'White']
Reverse the case of all strings. For those strings which contain no letters, reverse the strings:
['gREEN', 'rED', 'oRANGE', 'yELLOW', '', 'wHITE']
Original list:
['Hello', '!@#', '!@#$', '123#@!']
Reverse the case of all strings. For those strings which contain no letters, reverse the strings:
['hELLO', '#@!', '$#@!', '!@#321']
Click me to see the sample solution

53. Product of Units in List

Write a Python program to find the product of the units digits in the numbers in a given list.
Input:
[12, 23]
Output:
6
Input:
[12, 23, 43]
Output:
18
Input:
[113, 234]
Output:
12
Input:
[1002, 2005]
Output:
10
Click me to see the sample solution

54. Remove Duplicates, Preserve Order

Write a Python program to remove duplicates from a list of integers, preserving order.
Input:
[1, 3, 4, 10, 4, 1, 43]
Output:
[1, 3, 4, 10, 43]
Input:
[10, 11, 13, 23, 11, 25, 23, 76, 99]
Output:
[10, 11, 13, 23, 25, 76, 99]
Click me to see the sample solution

55. Odd First and Last Digits

Write a Python program to find numbers that are greater than 10 and have odd first and last digits.
Input:
[1, 3, 79, 10, 4, 1, 39, 62]
Output:
[79, 39]
Input:
[11, 31, 77, 93, 48, 1, 57]
Output:
[11, 31, 77, 93, 57]
Click me to see the sample solution

56. Find Integer Exponent

Write a Python program to find an integer exponent x such that a^x = n.
Input:
a = 2 : n = 1024
Output:
10
Input:
a = 3 : n = 81
Output:
4
Input:
a = 3 : n = 1290070078170102666248196035845070394933441741644993085810116441344597492642263849
Output:
170
Click me to see the sample solution

57. Signed Sum of Magnitudes

Write a Python program to find the sum of the magnitudes of the elements in the array. This sum should have a sign that is equal to the product of the signs of the entries.
Input:
[1, 3, -2]
Output:
-6
Input:
[1, -3, 3]
Output:
-7
Input:
[10, 32, 3]
Output:
45
Input:
[-25, -12, -23]
Output:
-60
Click me to see the sample solution

58. Largest Even Number in Range

Write a Python program to find the biggest even number between two numbers inclusive.
Input:
m = 12
n = 51
Output:
50
Input:
m = 1
n = 79
Output:
78
Input:
m = 47
n = 53
Output:
52
Input:
m = 100
n = 200
Output:
200
Click me to see the sample solution

59. Validate Filenames

A valid filename should end in .txt, .exe, .jpg, .png, or .dll, and should have at most three digits, no additional periods. Write a Python program to create a list of True/False that determine whether candidate filename is valid or not.
Input:
['abc.txt', 'windows.dll', 'tiger.png', 'rose.jpg', 'test.py', 'win32.exe']
Output:
['Yes', 'Yes', 'Yes', 'Yes', 'No', 'Yes']
Input:
['.txt', 'windows.exe', 'tiger.jpeg', 'rose.c', 'test.java']
Output:
['No', 'Yes', 'No', 'No', 'No']
Click me to see the sample solution

60. Numbers Adjacent to Primes

Write a Python program to find a list of all numbers that are adjacent to a prime number in the list, sorted without duplicates.
Input:
[2, 17, 16, 0, 6, 4, 5]
Output:
[2, 4, 16, 17]
Input:
[1, 2, 19, 16, 6, 4, 10]
Output:
[1, 2, 16, 19]
Input:
[1, 2, 3, 5, 1, 16, 7, 11, 4]
Output:
[1, 2, 3, 4, 5, 7, 11, 16]
Click me to see the sample solution

61. Find Missing Number for Zero Total

Write a Python program to find the number which when appended to the list makes the total 0.
Input:
[1, 2, 3, 4, 5]
Output:
-15
Input:
[-1, -2, -3, -4, 5]
Output:
5
Input:
[10, 42, 17, 9, 1315182, 184, 102, 29, 15, 39, 755]
Output:
-1316384
Click me to see the sample solution

62. Dictionary Key with Odd Case

Write a Python program to find the dictionary key whose case is different from all other keys.
Input:
{'red': '', 'GREEN': '', 'blue': 'orange'}
Output:
GREEN
Input:
{'RED': '', 'GREEN': '', 'orange': '#125GD'}
Output:
orange
Click me to see the sample solution

63. Sum of Even Elements at Odd Indices

Write a Python program to find the sum of the even elements that are at odd indices in a given list.
Input:
[1, 2, 3, 4, 5, 6, 7]
Output:
12
Input:
[1, 2, 8, 3, 9, 4]
Output:
6
Click me to see the sample solution

64. Words with Prime Lengths

Write a Python program to find the string consisting of all the words whose lengths are prime numbers.
Input:
The quick brown fox jumps over the lazy dog.
Output:
The quick brown fox jumps the
Input:
Omicron Effect: Foreign Flights Won't Resume On Dec 15, Decision Later.
Output:
Omicron Effect: Foreign Flights Won't On Dec 15,
Click me to see the sample solution

65. Circular Shift of Digits

Write a Python program to shift the decimal digits n places to the left, wrapping the extra digits around. If the shift > the number of digits in n, reverse the string.
Input:
n = 12345 and shift = 1
Output:
Result = 23451
Input:
n = 12345 and shift = 2
Output:
Result = 34512
Input:
n = 12345 and shift = 3
Output:
Result = 45123
Input:
n = 12345 and shift = 5
Output:
Result = 12345
Input:
n = 12345 and shift = 6
Output:
Result = 54321
Click me to see the sample solution

66. Indices of Closest Pair

Write a Python program to find the indices of the closest pair from a list of numbers.
Input: [1, 7, 9, 2, 10]
Output:
[0, 3]
Input: [1.1, 4.25, 0.79, 1.0, 4.23]
Output:
[4, 1]
Input: [0.21, 11.3, 2.01, 8.0, 10.0, 3.0, 15.2]
Output:
[2, 5]
Click me to see the sample solution

67. ASCII Shift for String Transformation

Write a Python program to find a string which, when each character is shifted (ASCII incremented) by shift, gives the result.
Input:
Ascii character table
Shift = 1
Output:
@rbhhbg`q`bsdqs`akd
Input:
Ascii character table
Shift = -1
Output:
Btdjj!dibsbdufs!ubcmf
Click me to see the sample solution

68. Fives Divisible by 9 or 15

Write a Python program to find all 5's in integers less than n that are divisible by 9 or 15.
Input:
Value of n = 50
Output:
[[15, 1], [45, 1]]
Input:
Value of n = 65
Output:
[[15, 1], [45, 1], [54, 0]]
Input:
Value of n = 75
Output:
[[15, 1], [45, 1], [54, 0]]
Input:
Value of n = 85
Output:
[[15, 1], [45, 1], [54, 0], [75, 1]]
Input:
Value of n = 150
Output:
[[15, 1], [45, 1], [54, 0], [75, 1], [105, 2], [135, 2]]
Click me to see the sample solution

69. Rearrange Words by ASCII

Write a Python program to create a new string by taking a string, and word by word rearranging its characters in ASCII order.
Input: Ascii character table
Output:
Aciis aaccehrrt abelt
Input: maltos won
Output:
almost now
Click me to see the sample solution

70. First Negative Balance

Write a Python program to find the first negative balance from a given list of numbers that represent bank deposits and withdrawals.
Input:
[[12, -7, 3, -89, 14, 88, -78], [-1, 2, 7]]
Output:
[-81, -1]
Input:
[[1200, 100, -900], [100, 100, -2400]]
Output:
[None, -2200]
Click me to see the sample solution

71. Inject Separator Between Numbers

Given a list of numbers and a number to inject, write a Python program to create a list containing that number in between each pair of adjacent numbers.
Input: [12, -7, 3, -89, 14, 88, -78, -1, 2, 7]
Separator: 6
Output:
[12, 6, -7, 6, 3, 6, -89, 6, 14, 6, 88, 6, -78, 6, -1, 6, 2, 6, 7]
Input: [1, 2, 3, 4, 5, 6]
Separator: 9
Output:
[1, 9, 2, 9, 3, 9, 4, 9, 5, 9, 6]
Click me to see the sample solution

72. Indices of Three Numbers Summing to Zero

Write a Python program to find the indices of three numbers that sum to 0 in a given list of numbers.
Input: [12, -7, 3, -89, 14, 4, -78, -1, 2, 7]
Output:
[1, 2, 5]
Input: [1, 2, 3, 4, 5, 6, -7]
Output:
[2, 3, 6]
Click me to see the sample solution

73. Vowel Between Consonants Substring

Write a Python program to find a substring in a given string that contains a vowel between two consonants.
Input: Hello
Output:
Hel
Input: Sandwhich
Output:
San
Input: Python
Output:
hon
Click me to see the sample solution

74. Space-Separated Characters with Counts

Write a Python program to find a string consisting of space-separated characters with given counts.
Input: {'f': 1, 'o': 2}
Output:
f o o
Input: {'a': 1, 'b': 1, 'c': 1}
Output:
a b c
Click me to see the sample solution

75. Reorder Numbers Based on Sum

Write a Python program to reorder numbers from a given array in increasing/decreasing order based on whether the first plus last element is odd/even.
Reorder numbers of a give array in increasing/decreasing order based on whether the first plus last element is odd/even.:
Input:
[3, 7, 4]
Output:
[3, 4, 7]
Input:
[2, 7, 4]
Output:
[7, 4, 2]
Input:
[1, 5, 6, 7, 4, 2, 8]
Output:
[1, 2, 4, 5, 6, 7, 8]
Input:
[1, 5, 6, 7, 4, 2, 9]
Output:
[9, 7, 6, 5, 4, 2, 1]
Click me to see the sample solution

76. Largest Prime Index and Digit Sum

Write a Python program to find the index of the largest prime in the list and the sum of its digits.
Input: [3, 7, 4]
Output:
[1, 7]
Input: [3, 11, 7, 17, 19, 4]
Output:
[4, 10]
Input: [23, 17, 201, 14, 10473, 43225, 421, 423, 11, 10, 2022, 342157]
Output:
[6, 7]
Click me to see the sample solution

77. GPA to Letter Grade Conversion

Write a Python program to convert GPAs to letter grades according to the following table:

78. Closest Distinct Pair in List

Write a Python program to find the two closest distinct numbers in a given list of numbers.
Input:
[1.3, 5.24, 0.89, 21.0, 5.27, 1.3]
Output:
[5.24, 5.27]
Input:
[12.02, 20.3, 15.0, 19.0, 11.0, 14.99, 17.0, 17.0, 14.4, 16.8]
Output:
[14.99, 15.0]
Click me to see the sample solution

79. Largest Negative and Smallest Positive Numbers

Write a Python program to find the largest negative and smallest positive numbers (or 0 if none).
Input:
[-12, -6, 300, -40, 2, 2, 3, 57, -50, -22, 12, 40, 9, 11, 18]
Output:
[-6, 2]
Input:
[-1, -2, -3, -4]
Output:
[-1, 0]
Input:
[1, 2, 3, 4]
Output:
[0, 1]
Input:
[]
Output:
[0, 0]
Click me to see the sample solution

80. Running Total of Integer Squares

Write a Python program to round each float in a given list of numbers up to the next integer and return the running total of the integer squares.
Input: [2.6, 3.5, 6.7, 2.3, 5.6]
Output:
[9, 25, 74, 83, 119]
Input: [301.1, 401.4, -23.1, 13554122.0, 10201.0101, 10000000.0]
Output:
[91204, 252808, 253337, 183714223444221, 183714327525025, 283714327525025]
Click me to see the sample solution

81. Average in Binary of a Range

Write a Python program to calculate the average of the numbers a through b (b not included) rounded to the nearest integer, in binary (or -1 if there are no such numbers).
Input:
4 , 7
Output:
0b101
Input:
11 , 19
Output:
0b1110
Click me to see the sample solution

82. Increasing Odd-Digit Sublist

Write a Python program to find the sublist of numbers from a given list of numbers with only odd digits in increasing order.
Input:
[1, 3, 79, 10, 4, 2, 39]
Output:
[1, 3, 39, 79]
Input:
[11, 31, 40, 68, 77, 93, 48, 1, 57]
Output:
[1, 11, 31, 57, 77, 93]
Input:
[9, -2, 3, 4, -2, 0, 2, -3, 8, -1]
Output:
[-3, -1, 3, 9]
Click me to see the sample solution

83. Indices for Unhappy String

A string is happy if every three consecutive characters are distinct. Write a Python program to find two indices associated with a given string being unhappy.
Input:
Python
Output:
None
Input:
Unhappy
Output:
[4, 5]
Input:
Find
Output:
None
Input:
Street
Output:
[3, 4]
Click me to see the sample solution

84. Matching Parentheses Indices

Write a Python program to find the index of the matching parentheses for each character in a given string.
Input: ()(())
Output:
[1, 0, 5, 4, 3, 2]
Input: ()()()
Output:
[1, 0, 3, 2, 5, 4]
Input: ((()))
Output:
[5, 4, 3, 2, 1, 0]
Click me to see the sample solution

85. Increasing Sequence from List

Write a Python program to find an increasing sequence consisting of the elements of the original list.
Input:
[1, 3, 79, 10, 4, 2, 39]
Output:
[1, 2, 3, 4, 10, 39, 79]
Input:
[11, 31, 40, 68, 77, 93, 48, 1, 57]
Output:
[1, 11, 31, 40, 48, 57, 68, 77, 93]
Input:
[9, -2, 3, 4, -2, 0, 2, -3, 8, -1]
Output:
[-3, -2, -1, 0, 2, 3, 4, 8, 9]
Click me to see the sample solution

86. Extract Vowels with Y as Vowel

Write a Python program to find the vowels from each of the original texts (y counts as a vowel at the end of the word) from a given list of strings.
Input: ['w3resource', 'Python', 'Java', 'C++']
Output:
['eoue', 'o', 'aa', '']
Input: ['ably', 'abruptly', 'abecedary', 'apparently', 'acknowledgedly']
Output:
['ay', 'auy', 'aeeay', 'aaey', 'aoeey']
Click me to see the sample solution

87. Valid Substring with Nested Brackets

Write a Python program to find a valid substring of a given string that contains matching brackets, at least one of which is nested.
Input:
]][][[]]]
Output:
[[]]
Input:
]]]]]]]]]]]]]]]]][][][][]]]]]]]]]]][[[][[][[[[[][][][]][[[[[[[[[[[[[[[[[[
Output:
[[][][][]]
Click me to see the sample solution

88. Integer with Specified Even and Odd Digits

Write a Python program to find an integer (n >= 0) with the given number of even and odd digits.
Input:
Number of even digits: 2 ,Number of odd digits: 3
Output:
22333
Input:
Number of even digits: 4 ,Number of odd digits: 7
Output:
22223333333
Click me to see the sample solution

89. Integers as Product of Three Primes

Write a Python program to find all integers <= 1000 that are the product of exactly three primes. Each integer should be represented as a list of its three prime factors.
Input: 10
Output:
[[2, 2, 2]]
Input: 50
Output:
[[2, 2, 2], [2, 2, 3], [2, 2, 5], [2, 2, 7], [2, 2, 11], [2, 3, 2], [2, 3, 3], [2, 3, 5], [2, 3, 7], [2, 5, 2], [2, 5, 3], [2, 5, 5], [2, 7, 2], [2, 7, 3], [2, 11, 2], [3, 2, 2], [3, 2, 3], [3, 2, 5], [3, 2, 7], [3, 3, 2], [3, 3, 3], [3, 3, 5], [3, 5, 2], [3, 5, 3], [3, 7, 2], [5, 2, 2], [5, 2, 3], [5, 2, 5], [5, 3, 2], [5, 3, 3], [5, 5, 2], [7, 2, 2], [7, 2, 3], [7, 3, 2], [11, 2, 2]]
Click me to see the sample solution

90. Appetite and Stock Calculation

For each triple of eaten, need, and stock, write a Python program to get a pair of total appetite and remaining.
Input:
[[2, 5, 6], [3, 9, 22]]
Output:
[[7, 1], [12, 13]]
Input:
[[2, 3, 18], [4, 9, 2], [2, 5, 7], [3, 8, 12], [4, 9, 106]]
Output:
[[5, 15], [6, 0], [7, 2], [11, 4], [13, 97]]
Input:
[[1, 2, 3], [4, 5, 6]]
Output:
[[3, 1], [9, 1]]
Click me to see the sample solution

91. Find n-Digit Integers Starting or Ending with 2

Write a Python program to find all n-digit integers that start or end with 2.
Input: 1
Output:
[2]
Input: 2
Output:
[12, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 32, 42, 52, 62, 72, 82, 92]
Input: 3
Output:
[102, 112, 122, 132, 142, 152, 162, 172, 182, 192, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 302, 312, 322, 332, 342, 352, 362, 372, 382, 392, 402, 412, 422, 432, 442, 452, 462, 472, 482, 492, 502, 512, 522, 532, 542, 552, 562, 572, 582, 592, 602, 612, 622, 632, 642, 652, 662, 672, 682, 692, 702, 712, 722, 732, 742, 752, 762, 772, 782, 792, 802, 812, 822, 832, 842, 852, 862, 872, 882, 892, 902, 912, 922, 932, 942, 952, 962, 972, 982, 992]
Click me to see the sample solution

92. Sort Keeping Every Other Element Fixed

Write a Python program to start with a list of integers, keep every other element in place and otherwise sort the list.
Input:
[2, 5, 6, 3, 1, 4, 34]
Output:
[1, 5, 2, 3, 6, 4, 34]
Input:
[8, 0, 7, 2, 9, 4, 1, 2, 8, 3]
Output:
[1, 0, 7, 2, 8, 4, 8, 2, 9, 3]
Click me to see the sample solution

93. Closest Palindrome to String

Write a Python program to find the closest palindrome to a given string.
Input:
cat
Output:
cac
Input:
madan
Output:
madam
Input:
radivider
Output:
radividar
Input:
madan
Output:
madam
Input:
abc
Output:
aba
Input:
racecbr
Output:
racecar
Click me to see the sample solution

94. Split Matched Parentheses Groups

Given a string consisting of whitespace and groups of matched parentheses, write a Python program to split it into groups of perfectly matched parentheses without any whitespace.
Input:
( ()) ((()()())) (()) ()
Output:
['(())', '((()()()))', '(())', '()']
Input:
() (( ( )() ( )) ) ( ())
Output:
['()', '((()()()))', '(())']
Click me to see the sample solution

95. Generate Palindrome of Specific Length

Write a Python program to generate a palindrome of a given length from a string.
Input: madam , 7
Output:
madaadam
Input: madam , 6
Output:
maddam
Input: madam , 5
Output:
maaaam
Input: madam , 3
Output:
maam
Input: madam , 2
Output:
mm
Input: madam , 1
Output:
aa
Click me to see the sample solution

96. Single Digits to English Words in Reverse Order

Write a Python program to get the single digits in numbers sorted backwards and converted into English words.
Input:
[1, 3, 4, 5, 11]
Output:
['five', 'four', 'three', 'one']
Input:
[27, 3, 8, 5, 1, 31]
Output:
['eight', 'five', 'three', 'one']
Click me to see the sample solution

97. Strange Sort: Alternating Min-Max

Write a Python program to find the following strange sort of list of numbers: the first element is the smallest, the second is the largest of the remaining, the third is the smallest of the remaining, the fourth is the smallest of the remaining, etc.
Input:
[1, 3, 4, 5, 11]
Output:
[1, 11, 3, 5, 4]
Input:
[27, 3, 8, 5, 1, 31]
Output:
[1, 31, 3, 27, 5, 8]
Input:
[1, 2, 7, 3, 4, 5, 6]
Output:
[1, 7, 2, 6, 3, 5, 4]
Click me to see the sample solution

98. Depth of Matched Parentheses Groups

Given a string consisting of groups of matched nested parentheses separated by parentheses, write a Python program to compute the depth of each group.
Input: (()) (()) () ((()()()))
Output:
[2, 2, 1, 3]
Input: () (()) () () () ()
Output:
[1, 2, 1, 1, 1, 1]
Input: (((((((()))))))) () (()) ((()()()))
Output:
[8, 1, 2, 3]
Click me to see the sample solution

99. Replace Spaces with Underscore and Hyphen

Write a Python program to find a string such that, when three or more spaces are compacted to a '-' and one or two spaces are replaced by underscores, leads to the target.
Input: Python-Exercises
Output:
Python Exercises
Input: Python_Exercises
Output:
Python Exercises
Input: -Hello,_world!__This_is-so-easy!-
Output:
Hello, world! This is so easy!
Click me to see the sample solution

100. Four Even Integers Summing to n

Write a Python program to find four positive even integers whose sum is a given integer.
Input:
n = 100
Output:
[94, 2, 2, 2]
Input:
n = 1000
Output:
[994, 2, 2, 2]
Input:
n = 10000
Output:
[9994, 2, 2, 2]
Input:
n = 1234567890
Output:
[1234567884, 2, 2, 2]
Click me to see the sample solution

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