Python: Create a list whose i^th element is the maximum of the first i elements of the input list

Python Programming Puzzles: Exercise-24 with Solution

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]

Visual Presentation:

Sample Solution-1:

Python Code:

# License: https://bit.ly/3oLErEI

# Define a function named 'test' that takes a list of numbers 'nums' as input
def test(nums):
    # List comprehension to create a list of maximum values for each prefix of the input list
    # Iterate through the indices from 1 to the length of 'nums' + 1
    # For each index 'i', find the maximum value in the prefix nums[:i]
    return [max(nums[:i]) for i in range(1, len(nums) + 1)]

# Assign a specific list of numbers 'nums' to the variable
nums = [0, -1, 3, 8, 5, 9, 8, 14, 2, 4, 3, -10, 10, 17, 41, 22, -4, -4, -15, 0]

# Print the original list of numbers 'nums'
print("Original list:")
print(nums)

# Print a message indicating the operation to be performed
print("List whose ith element is the maximum of the first i elements of the said list:")

# Print the result of the test function applied to the 'nums' list
print(test(nums))

# Assign a different list of numbers 'nums' to the variable
nums = [6, 5, 4, 3, 2, 1]

# Print the original list of numbers 'nums'
print("\nOriginal list:")
print(nums)

# Print a message indicating the operation to be performed
print("List whose ith element is the maximum of the first i elements of the said list:")

# Print the result of the test function applied to the updated 'nums' list
print(test(nums))

# Assign another list of numbers 'nums' to the variable
nums = [1, 19, 5, 15, 5, 25, 5]

# Print the original list of numbers 'nums'
print("\nOriginal list:")
print(nums)

# Print a message indicating the operation to be performed
print("List whose ith element is the maximum of the first i elements of the said list:")

# Print the result of the test function applied to the updated 'nums' list
print(test(nums))

Sample Output:

Original list:
[0, -1, 3, 8, 5, 9, 8, 14, 2, 4, 3, -10, 10, 17, 41, 22, -4, -4, -15, 0]
List whose ith element is the maximum of the first i elements of the said list:
[0, 0, 3, 8, 8, 9, 9, 14, 14, 14, 14, 14, 14, 17, 41, 41, 41, 41, 41, 41]

Original list:
[6, 5, 4, 3, 2, 1]
List whose ith element is the maximum of the first i elements of the said list:
[6, 6, 6, 6, 6, 6]

Original list:
[1, 19, 5, 15, 5, 25, 5]
List whose ith element is the maximum of the first i elements of the said list:
[1, 19, 19, 19, 19, 25, 25]

Flowchart:

Sample Solution-2:

Python Code:

# License: https://bit.ly/3oLErEI

# Define a function named 'test' that takes a list of numbers 'nums' as input
def test(nums):
    # List comprehension to create a list of maximum values for each prefix of the input list
    # Iterate through the indices from 0 to the length of 'nums'
    # For each index 'i', find the maximum value in the prefix nums[:i+1]
    return [max(nums[:i+1]) for i in range(len(nums))]

# Assign a specific list of numbers 'nums' to the variable
nums = [0, -1, 3, 8, 5, 9, 8, 14, 2, 4, 3, -10, 10, 17, 41, 22, -4, -4, -15, 0]

# Print the original list of numbers 'nums'
print("Original list:")
print(nums)

# Print a message indicating the operation to be performed
print("List whose ith element is the maximum of the first i elements of the said list:")

# Print the result of the test function applied to the 'nums' list
print(test(nums))

# Assign a different list of numbers 'nums' to the variable
nums = [6, 5, 4, 3, 2, 1]

# Print the original list of numbers 'nums'
print("\nOriginal list:")
print(nums)

# Print a message indicating the operation to be performed
print("List whose ith element is the maximum of the first i elements of the said list:")

# Print the result of the test function applied to the updated 'nums' list
print(test(nums))

# Assign another list of numbers 'nums' to the variable
nums = [1, 19, 5, 15, 5, 25, 5]

# Print the original list of numbers 'nums'
print("\nOriginal list:")
print(nums)

# Print a message indicating the operation to be performed
print("List whose ith element is the maximum of the first i elements of the said list:")

# Print the result of the test function applied to the updated 'nums' list
print(test(nums))

Sample Output:

Original list:
[0, -1, 3, 8, 5, 9, 8, 14, 2, 4, 3, -10, 10, 17, 41, 22, -4, -4, -15, 0]
List whose ith element is the maximum of the first i elements of the said list:
[0, 0, 3, 8, 8, 9, 9, 14, 14, 14, 14, 14, 14, 17, 41, 41, 41, 41, 41, 41]

Original list:
[6, 5, 4, 3, 2, 1]
List whose ith element is the maximum of the first i elements of the said list:
[6, 6, 6, 6, 6, 6]

Original list:
[1, 19, 5, 15, 5, 25, 5]
List whose ith element is the maximum of the first i elements of the said list:
[1, 19, 19, 19, 19, 25, 25]

Flowchart:

Python Code Editor :

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Find the indices for which the numbers in the list drops.
Next: Find the XOR of two given strings interpreted as binary numbers.