Java Basic Programming : Exercises, Practice, Solution
Java Basic Exercises [151 to 249 exercises with solution]
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151. Evaluate Expressions
Write a Java program to find the value of a specified expression.
a) 101 + 0) / 3
b) 3.0e-6 * 10000000.1
c) true && true
d) false && true
e) (false && false) || (true && true)
f) (false || false) && (true && true)
(101 + 0) / 3)-> 33
(3.0e-6 * 10000000.1)-> 30.0000003
(true && true)-> true
(false && true)-> false
((false && false) || (true && true))-> true
(false || false) && (true && true)-> false
152. Check Four Numbers Equal
Write a Java program that accepts four integers from the user and prints equal if all four are equal, and not equal otherwise.
Sample Output:
Input first number: 25
Input second number: 37
Input third number: 45
Input fourth number: 23
Numbers are not equal!
153. Test Doubles Between 0 and 1
Write a Java program that accepts two double variables and test if both strictly between 0 and 1 and false otherwise.
Sample Output:
Input first number: 5
Input second number: 1
false
154. Print Boolean Matrix
Write a Java program to print the contents of a two-dimensional Boolean array where t represents true and f represents false.
Sample array:
array = {{true, false, true},
{false, true, false}};
Expected Output :
t f t
f t f
155. Transpose 2D Array
Write a Java program to print an array after changing the rows and columns of a two-dimensional array.
Original Array:
10 20 30
40 50 60
After changing the rows and columns of the said array:10 40
20 50
30 60
156. Largest Integer Base-2 Logarithm
Write a Java program that returns the largest integer but not larger than the base-2 logarithm of a specified integer.
Original Number: 2350
Result: 115
157. GCD Using Euclid's Algorithm
Write a Java program to prove that Euclid’s algorithm computes the greatest common divisor of two integers that have positive values.
According to Wikipedia "The Euclidean algorithm is based on the principle that the greatest common divisor of two numbers does not change if the larger number is replaced by its difference with the smaller number. For example, 21 is the GCD of 252 and 105 (as 252 = 21 × 12 and 105 = 21 × 5), and the same number 21 is also the GCD of 105 and 252 − 105 = 147. Since this replacement reduces the larger of the two numbers, repeating this process gives successively smaller pairs of numbers until the two numbers become equal. When that occurs, they are the GCD of the original two numbers. By reversing the steps, the GCD can be expressed as a sum of the two original numbers each multiplied by a positive or negative integer, e.g., 21 = 5 × 105 + (−2) × 252. The fact that the GCD can always be expressed in this way is known as Bézout's identity."
Expected Output:
result: 24
result: 1
158. 2D Prime Matrix
Write a Java program to create a two-dimensional array (m x m) A[][] such that A[i][j] is false if I and j are prime otherwise A[i][j] becomes true.
Sample Output:
true true true
true true true
true true false
159. Find K Largest Elements
Write a Java program to find the k largest elements in a given array. Elements in the array can be in any order.
Expected Output:
Original Array:
[1, 4, 17, 7, 25, 3, 100]
3 largest elements of the said array are:
100 25 17
160. Find K Smallest Elements
Write a Java program to find the k smallest elements in a given array. Elements in the array can be in any order.
Expected Output:
Original Array:
[1, 4, 17, 7, 25, 3, 100]
3 largest elements of the said array are:
100 25 17
161. Kth Smallest and Largest
Write a Java program to find the kth smallest and largest element in a given array. Elements in the array can be in any order.
Expected Output:
Original Array:
[1, 4, 17, 7, 25, 3, 100]
K'th smallest element of the said array:
3
K'th largest element of the said array:
25
162. Numbers Greater Than Average
Write a Java program that finds numbers greater than the average of an array.
Expected Output:
Original Array:
[1, 4, 17, 7, 25, 3, 100]
The average of the said array is: 22.0
The numbers in the said array that are greater than the average are:
25
100
163. Binary Zeros Count
Write a Java program that will accept an integer and convert it into a binary representation. Now count the number of bits equal to zero in this representation.
Expected Output:
Input first number: 25
Binary representation of 25 is: 11001
Number of zero bits: 2
164. Divide Using Subtraction
Write a Java program to divide the two given integers using the subtraction operator.
Expected Output:
Input the dividend: 625
Input the divider: 25
Result: 25.0
165. Move Positives Right
Write a Java program to move every positive number to the right and every negative number to the left of a given array of integers.
Expected Output:
Original array: [-2, 3, 4, -1, -3, 1, 2, -4, 0]
Result: [-4, -3, -2, -1, 0, 1, 2, 3, 4]
166. Integer to String Format
Write a Java program to transform a given integer into String format.
Expected Output:
Input an integer: 35
String format of the said integer: 35
167. Move Zeros to Right
Write a Java program to move every zero to the right side of a given array of integers.
Original array: [0, 3, 4, 0, 1, 2, 5, 0]
Result: [3, 4, 1, 2, 5, 0, 0, 0]
168. Multiply Without Operator
Write a Java program to multiply two given integers without using the multiply operator (*).
Input the first number: 25
Input the second number: 5
Result: 125
169. Reverse Sentence Without Words
Write a Java program to reverse a sentence (assume a single space between two words) without reverse every word.
Input a string: The quick brown fox jumps over the lazy dog
Result: dog lazy the over jumps fox brown quick The
170. Longest Consecutive Sequence
Write a Java program to find the length of the longest consecutive sequence in a given array of integers.
Original array: [1, 1, 2, 3, 3, 4, 5, 2, 4, 5, 6, 7, 8, 9, 6, -1, -2]
7
171. Test Substring in String
Write a Java program to accept two strings and test if the second string contains the first one.
Input first string: Once in a blue moon
Input second string: See eye to eye
If the second string contains the first one? false
172. Elements Smaller Than Another Array
Write a Java program to get the number of elements in a given array of integers that are smaller than the integer in another given array of integers.
Expected Output:
0
3
7
173. Median in Sliding Window
Write a Java program to find the median of the numbers inside the window (size k) at each step in a given array of integers with duplicate numbers. Move the window to the array start.
Sample Output:
{|1, 2, 3|, 4, 5, 6, 7, 8, 8} -> Return median 2
{1, |2, 3, 4|, 5, 6, 7, 8, 8} -> Return median 3
{1, 2, |3, 4, 5|, 6, 7, 8, 8} -> Return median 4
{1, 2, 3, |4, 5, 6|, 7, 8, 8} -> Return median 5
{1, 2, 3, 4, |5, 6, 7|, 8, 8} -> Return median 6
{1, 2, 3, 4, 5, |6, 7, 8|, 8} -> Return median 7
{1, 2, 3, 4, 5, 6, |7, 8, 8|} -> Return median 8
Result array {2, 3, 4, 5, 6, 7, 8}
Expected Output:
Original array: [1, 2, 3, 4, 5, 6, 7, 8, 8] Value of k: 3 Result: 2 3 4 5 6 7 8
174. Max in Sliding Window
Write a Java program to find the maximum number inside the number in the window (size k) at each step in a given array of integers with duplicate numbers. Move the window to the top of the array.
Sample output:
{|1, 2, 3|, 4, 5, 6, 7, 8, 8} -> Return maximum 3
{1, |2, 3, 4|, 5, 6, 7, 8, 8} -> Return maximum 4
{1, 2, |3, 4, 5|, 6, 7, 8, 8} -> Return maximum 5
{1, 2, 3, |4, 5, 6|, 7, 8, 8} -> Return maximum 6
{1, 2, 3, 4, |5, 6, 7|, 8, 8} -> Return maximum 7
{1, 2, 3, 4, 5, |6, 7, 8|, 8} -> Return maximum 8
{1, 2, 3, 4, 5, 6, |7, 8, 8|} -> Return maximum 8
Result array {3, 4, 5, 6, 7, 8, 8}
Expected Output:
Original array: [1, 2, 3, 4, 5, 6, 7, 8, 8] Value of k: 3 Result: 2 3 4 5 6 7 8
175. Delete Middle Node in Linked List
Write a Java program to delete a specified node in the middle of a singly linked list.
Sample Singly linked list: 10->20->30->40->50
Delete the fourth node i.e. 40
Result: 10->20->30->50
Expected Output:
Original Linked list: 10->20->30->40->50 After deleting the fourth node, Linked list becomes: 10->20->30->50
176. Partition Even and Odd
Write a Java program that partitions an array of integers into even and odd numbers.
Expected Output
Original array: [7, 2, 4, 1, 3, 5, 6, 8, 2, 10] After partition the said array becomes: [10, 2, 4, 2, 8, 6, 5, 3, 1, 7]
177. Clone Binary Tree
Write a Java program to get an updated binary tree with the same structure and value as a given binary tree.
Expected Output:
Original Treenode: 4 5 2 3 1 Clone of the said Treenode: 4 5 2 3 1
178. Longest Increasing Subsequence
Write a Java program to find the longest increasing continuous subsequence in a given array of integers.
Expected Output:
Original array: [10, 11, 12, 13, 14, 7, 8, 9, 1, 2, 3] Size of longest increasing continuous subsequence: 5
179. Add One to Array Number
Write a Java program to add one to a positive number represented as an array of digits.
Sample array: [9, 9, 9, 9] which represents 9999
Output: [1, 0, 0, 0, 0].
Expected Output:
Original array: [9, 9, 9, 9] Array of digits: [1, 0, 0, 0, 0]
180. Swap Adjacent Nodes in List
Write a Java program to swap two adjacent nodes in a linked list.
Expected Output:
Original Linked list: 10->20->30->40->50 After swiping Linked list becomes: 20->10->40->30->50
181. Length of Last Word
Write a Java program to find the length of the last word in a given string. The string contains upper/lower-case alphabets and empty space characters like ' '.
Sample Output:
Original String: The length of last word Length of the last word of the above string: 4
182. Check Identical Binary Trees
Write a Java program to check if two binary trees are identical. Assume that two binary trees have the same structure and every identical position has the same value.
Sample Output:
Comparing TreeNode a and TreeNode b: false Comparing TreeNode b and TreeNode c: true
183. Sum Digits to Single Digit
Write a Java program to accept a positive number and repeatedly add all its digits until the result has only one digit.
Expected Output:
Input a positive integer: 25 7
184. Longest Consecutive Path in Tree
Write a Java program to find the length of the longest consecutive sequence path in a given binary tree.
Note: The longest consecutive path need to be from parent to child.
Expected Output:
Length of the longest consecutive sequence path: 4
185. Check Isomorphic Strings
Write a Java program to check if two strings are isomorphic or not.
Expected Output:
Is abca and zbxz are Isomorphic? true
186. Check Strobogrammatic Number
Write a Java program to check if a number is a strobogrammatic number. The number is represented as a string.
According to Wikipedia "A strobogrammatic number is a number whose numeral is rotationally symmetric, so that it appears the same when rotated 180 degrees. In other words, the numeral looks the same right-side up and upside down (e.g., 69, 96, 1001). A strobogrammatic prime is a strobogrammatic number that is also a prime number, i.e., a number that is only divisible by one and itself (e.g., 11). It is a type of ambigram, words and numbers that retain their meaning when viewed from a different perspective, such as palindromes."
The first few strobogrammatic numbers are:
0, 1, 8, 11, 69, 88, 96, 101, 111, 181, 609, 619, 689, 808, 818, 888, 906, 916, 986, 1001, 1111, 1691, 1881, 1961, 6009, 6119, 6699, 6889, 6969, 8008, 8118, 8698, 8888, 8968, 9006, 9116, 9696, 9886, 9966, ...
Expected Output:
Is 9006 is Strobogrammatic? true
187. First Non-Repeating Character
Write a Java program to find the index of the first non-repeating character in a given string.
Expected Output:
Index of first non-repeating character in 'google' is: 4
188. Find Anagram Start Indices
Write a Java program to find all the start indices of a given string's anagrams in another given string.
Expected Output:
Original String: zyxwyxyxzwxyz Starting anagram indices of xyz: [0, 6, 10]
189. Sum Two Numbers as Strings
Write a Java program to two non-negative integers num1 and num2 represented as strings, return the sum of num1 and num2.
Expected Output:
'123' + '456' = 579
190. Find Missing String
Write a Java program to find the missing string from two given strings.
Expected Output:
Missing string: [Solution]
191. Sum of Two Squares
Write a Java program to test whether there are two integers x and y such that x^2 + y^2 is equal to a given positive number.
Expected Output:
Input a positive integer: 25 Is 25 sum of two square numbers? true
192. Rearrange Letters and Sum Digits
Write a Java program to rearrange the alphabets in the order followed by the sum of digits in a given string containing uppercase alphabets and integer digits (from 0 to 9).
Expected Output:
ADEHNS23
193. Subset Sums of Natural Numbers
Write a Java program that accepts an integer and sums the elements from all possible subsets of a set formed by the first n natural numbers.
Expected Output:
Input a positive integer: 25 Sum of subsets of n is : 1157627904
194. Find Positions in Matrix
Write a Java program to determine the all positions of a given number in a given matrix. If the number is not found print ("Number not found!").
Expected Output:
(0,2) (1,0) (2,1)
195. Check Triangle Validity
Write a Java program to check if three given side lengths (integers) can make a triangle or not.
Expected Output:
Input side1: 5 Input side2: 6 Input side3: 8 Is the said sides form a triangle: true
196. Generate Spiral Matrix
rite a Java program to create a spiral array of n * n sizes from a given integer n.
Expected Output:
Input a number: 5 Spiral array becomes: 1 2 3 4 5 16 17 18 19 6 15 24 25 20 7 14 23 22 21 8 13 12 11 10 9
197. Check Perfect Square
Write a Java program to test if a given number (positive integer) is a perfect square or not.
Expected Output:
Input a positive integer: 6 Is the said number perfect square? false
198. Prime Number Position
Write a Java program to calculate the position of a given prime number.
Expected Output:
Input a positive integer: 15 Position of the said Prime number: 6
199. String Follows Pattern
Write a Java program to check if a string follows a given pattern.
Example pattern:
Given pattern = "xyyx", str = "red black black red", return true.
Given pattern = "xyyx", str = "red black black green", return false.
Given pattern = "xxxx", str = "red black black red", return false.
Given pattern = "xxxx", str = "red red red red", return true.
Expected Output:
Is the string and pattern matched? false
200. Remove Duplicate Letters
Write a Java program to remove duplicate letters and arrange them in lexicographical order from a given string containing only lowercase letters.
Note: In mathematics, the lexicographic or lexicographical order (also known as lexical order, dictionary order, alphabetical order or lexicographic(al) product) is a generalization of the way words are alphabetically ordered based on the alphabetical order of their component letters.
Expected Output:
Original string: zxywooxz After removing duplicate characters: xywoz
201. Divide Array into Equal Sum Subsets
Write a Java program to divide a given array of integers into given k non-empty subsets whose sums are all equal. Return true if all sums are equal otherwise return false.
Example:
nums = {1,3,3,5,6,6}, k = 4;
4 subsets (5,1), (3, 3), (6), (6) with equal sums.
Expected Output:
Original Array: [1, 3, 3, 5, 6, 6] Target of subsets: 4 After removing duplicate characters: true
202. Continuous Subarrays with Target Sum
Write a Java program to find the total number of continuous subarrays in a given array of integers whose sum equals an integer.
Expected Output:
Original Array: [4, 2, 3, 3, 7, 2, 4] Value of k: 6 Total number of continuous subarrays: 3
203. Max Average of Subarray
Write a Java program to find the contiguous subarray of given length k which has the maximum average value of a given array of integers. Display the maximum average value.
Expected Output:
Original Array: [4, 2, 3, 3, 7, 2, 4] Value of k: 3 Maximum average value: 4.333333333333333
204. Compute Modular Exponentiation
Write a Java program to compute xn % y where x, y and n are all 32-bit integers.
Expected Output:
Input x : 25 Input n : 35 Input y : 45 x^n % y = 5.0
205. Check If Power of Two in O(1)
Write a Java program to check whether an integer is a power of 2 or not using O(1) time.
Note: O(1) means that it takes a constant time, like 12 nanoseconds, or two minutes no matter the amount of data in the set.
O(n) means it takes an amount of time linear with the size of the set, so a set twice the size will take twice the time. You probably don't want to put a million objects into one of these.
Expected Output:
Input a number : 25 false
206. Generate CRC32 Checksum
From Wikipedia,
A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data. Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents. On retrieval, the calculation is repeated and, in the event the check values do not match, corrective action can be taken against data corruption. CRCs can be used for error correction.
Example:
Write a Java program to generate a CRC32 checksum of a given string or byte array.Input:
Input a string: The quick brown fox crc32 checksum of the string: b74574de
207. Merge Two Sorted Linked Lists
Write a Java program to merge two sorted (ascending) linked lists in ascending order.
Expected Output:
How many elements do you want to add in 1st linked list?: 3 Input numbers of 1st linked list in ascending order: 1 2 3 How many elements do you want to add in 2nd linked list?: 3 Input numbers of 2nd linked list in ascending order: 4 5 6 Merged list: 1 2 3 4 5 6
208. String Compression with Repeated Counts
Write a Java program to create a basic string compression method using repeated character counts.
Input string: aaaabbbbcccccddddeeee
Expected Output:
Enter a string (you can include space as well) aaaabbbbcccccddddeeee The compressed string along with the counts of repeated characters is: a4b4c5d4e4
209. Unique Combinations for Target Sum
Write a Java program to find all unique combinations from a collection of candidate numbers. The sum of the numbers will equal a given target number.
Input number of elements of the array:
3
Input number format: 2 3 4 5:
Expected Output:
Enter elements:
6 7 8
Enter target sum:
21
A solution set is:
{ 6 7 8 }
210. String Matching with Wildcards
Write a Java program to match any single character (use ?) or any sequence of characters (use *) including empty. The matching should cover the entire input string.
Expected Output:
Enter a string bb Enter a pattern b* Yes
211. Find Top Three Building Heights
Write a Java program to find the heights of the top three buildings in descending order from eight given buildings.
Input:
0 ≤ height of building (integer) ≤ 10,000
Expected Output:
Input the heights of eight buildings: 25 19 23 45 18 23 24 19 Heights of the top three buildings: 45 25 24
212. Digit Count of Sum of Two Integers
Write a Java program to compute the digit number of the sum of two given integers.
Input:
Each test case consists of two non-negative integers a and b which are separated by a space in a line. 0 ≤ a, b ≤ 1,000,000
Expected Output:
Input two integers(a b): 13 25 Digit number of sum of said two integers: 2
213. Check If Sides Form Right Triangle
Write a Java program to check whether three given lengths (integers) of three sides form a right triangle. Print "Yes" if the given sides form a right triangle otherwise print "No".
Input:
Each test case consists of two non-negative integers a and b which are separated by a space in a line. 0 ≤ a, b ≤ 1,000,000
Expected Output:
Input three integers(sides of a triangle) 6 9 12 If the given sides form a right triangle? No
214. Solve Linear Equations
Write a Java program which solve the equation:
ax+by=c
dx+ey=f
Print the values of x, y where a, b, c, d, e and f are given.
Input:
a,b,c,d,e,f separated by a single space.
(-1,000 ≤ a,b,c,d,e,f ≤ 1,000)
Expected Output:
Input the value of a, b, c, d, e, f: 5 6 8 9 7 4 -1.684 2.737
215. Compute Loan Debt After N Months
Write a Java program to compute the debt amount in n months. Monthly, the loan adds 4% interest to the $100,000 borrowed and rounds it to the nearest 1,000.
Input:
An integer n (0 ≤ n ≤ 100)
Expected Output:
Input number of months: 6 Amount of debt: 129000
216. Count Combinations for Sum N
Write a Java program which reads an integer n and finds the number of combinations of a,b,c and d (0 ≤ a,b,c,d ≤ 9) where (a + b + c + d) equals n.
Input:
a,b,c,d,e,f separated by a single space.
(-1,000 ≤ a,b,c,d,e,f ≤ 1,000)
Expected Output:
Input the number(n): 5 Number of combinations of a, b, c and d : 56
217. Count Prime Numbers ≤ N
Write a Java program to print the number of prime numbers less than or equal to a given integer.
Input:
n (1 ≤ n ≤ 999,999)
Expected Output:
Input the number(n): 1235 Number of prime numbers which are less than or equal to n.: 202
218. Compute Circle from Three Points
Write a Java program to compute the radius and central coordinates (x, y) of a circle constructed from three given points on the plane surface.
Input:
x1, y1, x2, y2, x3, y3 separated by a single space.
Expected Output:
Input x1, y1, x2, y2, x3, y3 separated by a single space: 5 6 4 8 7 9 Radius and the central coordinate: 1.821 (5.786 7.643)
219. Check Point Inside Triangle
Write a Java program to check if a point (x, y) is in a triangle or not. A triangle is formed by three points.
Input:
x1, y1, x2, y2, x3, y3 separated by a single space.
Expected Output:
Input (x1, y1) 2 6 Input (x2, y2) 3 5 Input (x3, y3) 4 6 Input (xp, yp) 5 6 The point is outside the triangle.
220. Sum of Two Large Integers with Overflow Check
Write a Java program to compute and print the sum of two given integers (more than or equal to zero). If the given integers or the sum have more than 80 digits, print "overflow".
Input:
Expected Output:
Input two integers: 25 46 Sum of the said two integers: 71
221. Sort Six Numbers in Descending Order
Write a Java program that accepts six numbers as input and sorts them in descending order.
Input:
Input consists of six numbers n1, n2, n3, n4, n5, n6 (-100000 ≤ n1, n2, n3, n4, n5, n6 ≤ 100000). The six numbers are separated by a space.
Expected Output:
Input six integers: 4 6 8 2 7 9 After sorting the said integers: 9 8 7 6 4 2
222. Test If Two Lines Are Parallel
Write a Java program to test whether two lines PQ and RS are parallel. The four points are P(x1, y1), Q(x2, y2), R(x3, y3), and S(x4, y4).
Input:
−100 ≤ x1, y1, x2, y2, x3, y3, x4, y4 ≤ 100
Each value is a real number with at most 5 digits after the decimal point.
Expected Output:
Input P(x1,y1),separated by a space. 5 6 Input Q(x2,y2),separated by a space. 4 2 Input R(x3,y3),separated by a space. 5 3 Input S(x4,y4),separated by a space. 5 6 Two lines are not parallel.
223. Maximum Sum of Contiguous Subsequence
Write a Java program to find the maximum sum of a contiguous subsequence from a given sequence of numbers a1, a2, a3, ... an. A subsequence of one element is also a continuous subsequence.
Input:
You can assume that 1 ≤ n ≤ 5000 and -100000 ≤ ai ≤ 100000.
Input numbers are separated by a space.
Input 0 to exit.
Expected Output:
How many integers would you like to input? 5 Input the integers: 25 61 35 42 66 Maximum sum of the said contiguous subsequence: 229
224. Test Relationship Between Two Circles
There are two circles C1 with radius r1, central coordinate (x1, y1) and C2 with radius r2 and central coordinate (x2, y2).
Write a Java program to test the followings -
"C2 is in C1" if C2 is in C1
"C1 is in C2" if C1 is in C2
"Circumference of C1 and C2 intersect" if circumference of C1 and C2 intersect, and
"C1 and C2 do not overlap" if C1 and C2 do not overlap.
Input:
Input numbers (real numbers) are separated by a space.
Expected Output:
Input x1, y1, r1: (numbers are separated by a space) 5 6 8 7 Input x2, y2, r2: (numbers are separated by a space) 8 9 5 4 C1 and C2 do not overlap
225. Find Day of the Week for a Date (2004)
Write a Java program that reads a date (from 2004/1/1 to 2004/12/31) and prints the day of the date. Jan. 1, 2004, was Thursday. Note that 2004 is a leap year.
Expected Output:
Input the month(1-12) 9 Input date (1-31) 15 Name of the date: Wednesday
226. Find Mode Values in Integer Sequence
Write a Java program to print mode values from a given sequence of integers. The mode value is the element that occurs most frequently. If there are several mode values, print them in ascending order.
Input:
A sequence of integer’s ai (1 ≤ ai ≤ 100). The number of integers is less than or equals to 100.
Expected Output:
How many integers would you like to input(Max.100?) 5 Input the integers: 25 35 15 5 45 Mode value(s)in ascending order: 5 15 25 35 45
227. Most Frequent and Longest Words in Text
Write a Java program that reads a text (only alphabetical characters and spaces) and prints two words. The first one is the word which is frequently used in the text. The second one is the word with the most letters.
Note: A word is a sequence of letters which is separated by the spaces.
Input:
A sequence of integer’s ai (1 ≤ ai ≤ 100). The number of integers is less than or equals to 100.
Expected Output:
Thank you for your comment and your participation. Input a text in a line: Most frequent text and the word which has the maximum number of letters: your participation.
228. Count Combinations of Digits with Target Sum
Write a Java program that reads n digits (given) chosen from 0 to 9 and prints the number of combinations where the sum of the digits equals another given number (s). Do not use the same digits in a combination.
For example, the combinations where n = 3 and s = 6 are as follows:
1 + 2 + 3 = 6
0 + 1 + 5 = 6
0 + 2 + 4 = 6
Input:
Two integers as number of combinations and their sum by a single space in a line. Input 0 0 to exit.
Expected Output:
Input number of combinations and sum (separated by a space in a line): 3 6 Number of combinations: 3
229. Check Rectangle or Rhombus from Parallelogram Sides
Write a Java program that reads the two adjoining sides and the diagonal of a parallelogram. It will check whether the parallelogram is a rectangle or a rhombus.
According to Wikipedia-
parallelograms: In Euclidean geometry, a parallelogram is a simple (non-self-intersecting) quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure.
rectangles: In Euclidean plane geometry, a rectangle is a quadrilateral with four right angles. It can also be defined as an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°). It can also be defined as a parallelogram containing a right angle.
rhombus: In plane Euclidean geometry, a rhombus (plural rhombi or rhombuses) is a simple (non-self-intersecting) quadrilateral whose four sides all have the same length. Another name is equilateral quadrilateral, since equilateral means that all of its sides are equal in length. The rhombus is often called a diamond, after the diamonds suit in playing cards which resembles the projection of an octahedral diamond, or a lozenge, though the former sometimes refers specifically to a rhombus with a 60° angle (see Polyiamond), and the latter sometimes refers specifically to a rhombus with a 45° angle.
Input:
Two adjoined sides and the diagonal.
1 ≤ ai, bi, ci ≤ 1000, ai + bi > ci
Expected Output:
Input two adjoined sides and the diagonal of a parallelogram (comma separated): 8,8,8 This is a rhombus.
230. Replace "python" with "java" and Vice Versa
Write a Java program to replace a string "python" with "java" and "java" with "python" in a given string.
Input:
English letters (including single byte alphanumeric characters, blanks, symbols) are given on one line. The length of the input character string is 1000 or less.
Output:
Exchanged character string of python and java on one line.
Expected Output:
Input the string: python is more propular than java New string: java is more propular than python
231. Difference Between Largest and Smallest Integer
Write a Java program to find the difference between the largest integer and the smallest integer. These integers are created by 8 numbers from 0 to 9. The number that can be rearranged starts with 0 as in 00135668.
Input:
Data is a sequence of 8 numbers (numbers from 0 to 9).
Output:
The difference between the largest integer and the smallest integer.
Sample Output:
Input an integer created by 8 numbers from 0 to 9: 567894321 Difference between the largest and the smallest integer from the given integer: 75308643
232. Sum of First n Prime Numbers
Write a Java program to compute the sum of the first n prime numbers.
Input:
n ( n ≤ 10000). Input 0 to exit the program.
Sample Output:
Input a number (n<=10000) to compute the sum: 100 Sum of first 100 prime numbers: 24133
233. Goldbach Combinations of Even Number
Write a Java program that accepts an even number (n should be greater than or equal to 4 and less than or equal to 50,000, a Goldbach number) from the user and creates combinations that express the given number as a sum of two prime numbers. Print the number of combinations.
Goldbach number: A Goldbach number is a positive even integer that can be expressed as the sum of two odd primes.[4] Since four is the only even number greater than two that requires the even prime 2 in order to be written as the sum of two primes, another form of the statement of Goldbach's conjecture is that all even integers greater than 4 are Goldbach numbers.
The expression of a given even number as a sum of two primes is called a Goldbach partition of that number. The following are examples of Goldbach partitions for some even numbers:
6 = 3 + 3
8 = 3 + 5
10 = 3 + 7 = 5 + 5
12 = 7 + 5
...
100 = 3 + 97 = 11 + 89 = 17 + 83 = 29 + 71 = 41 + 59 = 47 + 53
Sample Output:
Input an even number: 100 Number of combinations: 6
234. Maximum Regions from Straight Lines
If you draw a straight line on a plane, the plane is divided into two regions. For example, if you draw two straight lines in parallel, you get three areas. If you draw vertically from one to the other you get 4 areas.
Write a Java program to create the maximum number of regions obtained by drawing n given straight lines.
Input:
xp,yp, xq, yq, xr, yr, xs and ys are -100 to 100 respectively and each value can be up to 5 digits after the decimal point It is given as a real number including the number of.
Output: Yes or No.
Sample Output:
Input number of straight lines: 5 Number of regions: 16
235. Check Orthogonal Lines from Points
There are four different points on a plane: P(xp, yp), Q(xq, yq), R(xr, yr) and S(xs, ys). Write a Java program to test whether AB and CD are orthogonal or not.
Input:xp,yp, xq, yq, xr, yr, xs and ys are -100 to 100 respectively and each value can be up to 5 digits after the decimal point It is given as a real number including the number of.
Output: Yes or No.
Sample Output:
Input xp, yp, xq, yq, xr, yr, xs, ys: 3.5 4.5 2.5 -1.5 3.5 1.0 0.0 4.5 Two lines are not orthogonal.
236. Sum of Numerical Values in a Sentence
Write a Java program to sum all numerical values (positive integers) embedded in a sentence.
Input:
Sentences with positive integers are given over multiple lines. Each line is a character string containing one-byte alphanumeric characters, symbols, spaces, or an empty line. However the input is 80 characters or less per line and the sum is 10,000 or less.
Sample Output:
Input some text and numeric values: 5 apple and 10 orange are rotten in the basket Sum of the numeric values: 15
237. Count Islands from Grid
There are 10 vertical and horizontal squares on a plane. Each square is painted in blue and green. Blue represents the sea, and green represents the land. When two green squares are in contact with the top and bottom, or right and left, they are ground. The area created by only one green square is called an "island". For example, the figure below shows five islands.
Write a Java program to read the mass data and find the number of islands. .
Input:
A single data set is represented by 10 rows of 10 numbers representing green squares as 1 and blue squares as zeros.
Output: For each data set, output the number of islands.
Sample Output:
Input 10 rows of 10 numbers representing green squares (island) as 1 and blue squares (sea) as zeros 1100000111 1000000111 0000000111 0010001000 0000011100 0000111110 0001111111 1000111110 1100011100 1110001000 Number of islands: 5
238. Restore String from Compression Rule
When characters are consecutive in a string, it is possible to shorten it by replacing them with a certain rule. For example, the character string YYYYY, if it is expressed as # 5 Y, it is compressed by one character.
Write a Java program to restore the original string by entering the compressed string with this rule. However, the # character does not appear in the restored character string.
Note: The original sentences are uppercase letters, lowercase letters, numbers, symbols, less than 100 letters, and consecutive letters are not more than 9 letters.
Input:
Multiple character strings are given. One string is given per line.
Output: The restored character string for each character on one line.
Sample Output:
Input the text: XY#6Z1#4023 XYZZZZZZ1000023
239. Extract Words of Length 3 to 6 from Sentence
A search engine giant such as Google accepts thousands of web pages from around the world and categorizes them, creating a huge database of information. Search engines also analyze search keywords entered by the user and create database queries based on those keywords. In both cases, complicated processing is carried out to realize efficient retrieval, but the basics are all about cutting out words from sentences.
Write a Java program to cut out words of 3 to 6 characters length from a given sentence not more than 1024 characters.
Input:
English sentences consisting of delimiters and alphanumeric characters are given on one line.
Output: Output a word delimited by one space character on one line.
Sample Output:
Input a sentence (1024 characters. max.) The quick brown fox 3 to 6 characters length of words: The quick brown fox
240. Maximum Path Sum from Hilltop Data
As shown in Figure 1, arrange integers (0 to 99) as narrow hilltops. When reading such data from top to bottom, following the next rule represents a huge amount of data.
Write a Java program that computes the maximum value of the sum of the passing integers.
Input:
A series of integers separated by commas are given in diamonds. No spaces are included in each line. The input example corresponds to Figure 1. The number of lines of data is less than 100 lines.
Output: The maximum value of the sum of integers passing according to the rule on one line.
Sample Output:
Input the numbers (ctrl+c to exit): 8 4,9 9,2,1 3,8,5,5 5,6,3,7,6 3,8,5,5 9,2,1 4,9 8 Maximum value of the sum of integers passing according to the rule on one line. 64
241. Count Combinations Satisfying Sum of Variables
Write a Java program to find the number of combinations that satisfy p + q + r + s = n where n is a given number <= 4000 and p, q, r, s range from 0 to 1000.
Sample Output:
Input a positive integer: 252 Number of combinations of a,b,c,d: 2731135
242. Add Rows and Columns of Spreadsheet Table
Your task is to develop a small piece of spreadsheet software. Write a Java program that adds up the columns and rows of a given table as shown in the specified figure:
Input number of rows/columns (0 to exit) 4 25 69 51 26 68 35 29 54 54 57 45 63 61 68 47 59 Result: 25 69 51 26 171 68 35 29 54 186 54 57 45 63 219 61 68 47 59 235 208 229 172 202 811
243. Pair Words with Page Numbers
Write a Java program that reads a list of pairs of a word and a page number. It prints the words and a list of page numbers.
Input:
Input pairs of a word and a page number: apple 5 banana 6 Word and page number in alphabetical order: apple 5 banana 6
244. Validate String for XYZ Rules
Write a Java program that accepts a string from the user and checks whether it is correct or not.
The conditions for getting the "correct answer" are:
a) There must be only three characters X, Y, and Z in the string, and no other characters.
b) Any string of any form such as aXYZa can get the "correct answer", where a is either an empty string or a string consisting only of the letter X;
c) If aXbZc is true, aXbYZca is also valid, where a, b, c are either empty strings or a string consisting only of the letter X.
Input:
Input a string: XYZ Correct format..
245. Highest and Lowest Scores from Student Data
Write a Java program that accepts students' names, ids, and marks and displays their highest and lowest scores.
The student name and id are all strings of no more than 10 characters. The score is an integer between 0 and 100.
Input:
Input number of students: 3 Input Student Name, ID, Score: Devid v1 72 Peter v2 68 Johnson v3 85 name, ID of the highest score and the lowest score: Johnson v3 Peter v2
246. Convert 3-Digit Numbers to "HHTTT123" Format
Let us use the letter H to mean "hundred", the letter T to mean "ten" and “1, 2, . . . n” to represent the one digit n (<10). Using the given format, write a Java program that converts 3 digits positive numbers. For example, 234 should be output as BBSSS1234 because it has 2 "hundreds", 3 "ten", and 4 ones.
The student name and id are all strings of no more than 10 characters. The score is an integer between 0 and 100.
Input:
235
230
Output:
HHTTT12345
HHTTT
Input a positive number(max three digits): 235 Result: HHTTT12345
247. Check if Sum of Two Integers is Greater than Third
Write a Java program that accepts three integers and checks whether the sum of the first two integers is greater than the third integer. Three integers are in the interval [-231, 231 ].
Input:
Input three integers (a,b,c): 5 8 9 Check whether (a + b) is greater than c? true
248. Check if Word is Abecadrian
From Wikipedia, An abecedarium (or abecedary) is an inscription consisting of the letters of an alphabet, almost always listed in order. Typically, abecedaria (or abecedaries) are practice exercises.
Write a Java program to check if each letter of a given word (Abecadrian word) is less than the one before it.
Input:
Input a word: ABCD Is Abecadrian word? true
249. Hamming Weight of Integer (Count Set Bits)
From Wikipedia,
The Hamming weight of a string is the number of symbols that are different from the zero-symbol of the alphabet used. It is thus equivalent to the Hamming distance from the all-zero string of the same length. For the most typical case, a string of bits, this is the number of 1's in the string, or the digit sum of the binary representation of a given number and the ℓ₁ norm of a bit vector. In this binary case, it is also called the population count, popcount, sideways sum, or bit summation.
Example:
| String | Hamming weight |
|---|---|
| 11101 | 4 |
| 11101000 | 4 |
| 00000000 | 0 |
| 789012340567 | 10 |
Input:
Input a number: 1427 6
Java Code Editor:
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