Python: Compute the summation of the absolute difference of all distinct pairs in a given array

Python Basic - 1: Exercise-26 with Solution

Write a Python program to compute the summation of the absolute difference of all distinct pairs in a given array (non-decreasing order).

Sample array: [1, 2, 3]
Then all the distinct pairs will be:
1 2
1 3
2 3

Sample Solution:

Python Code:

def sum_distinct_pairs(arr):
    result = 0
    i = 0
    while i<len(arr):
        result+=i*arr[i]-(len(arr)-i-1)*arr[i]
        i+=1
    return result
print(sum_distinct_pairs([1,2,3]))
print(sum_distinct_pairs([1,4,5]))

Sample Output:

4
8

Pictorial Presentation:

Flowchart:

Python Code Editor:

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