Given a list of distinct elements, write a Python program to find the sum of absolute differences of all pairs in the given list.
Input : [9, 2, 14] Output : 24 Explanation: (abs(9-2) + abs(9-14) + abs(2-14)) Input : [1, 2, 3, 4] Output : 10 Explanation: (abs(1-2) + abs(1-3) + abs(1-4) + abs(2-3) + abs(2-4) + abs(3-4))
The first approach is the brute force approach, which has been previously discussed. Here, we will discuss the pythonic approaches.
Approach #1 : Using
Enumerate() method adds a counter to an iterable and returns it in a form of enumerate object. In this method, we have a list ‘diffs’ which contains the absolute difference. We use two loops having two variables each. One to iterate through the counter and one for the list element. In every iteration, we check if the elements are similar or not. If not, find absolute difference and append it to diffs. Finally, find the sum of list. Since each pair will be counted twice, we divide the final sum by 2 and return it.
Approach #2 : Using itertools
Python itertools consist of permutation() method. This method takes a list as an input and return an object list of tuples that contain all permutation in a list form. Here, to find absolute difference we essentially need a permutation of two elements. Since each pair will be counted twice, we divide the final sum by 2.
- Python | Maximum absolute difference list of list
- Python | Find all distinct pairs with difference equal to k
- Python program to find all possible pairs with given sum
- Python program to find sum of elements in list
- Python program to find Cumulative sum of a list
- Python program to find all Strong Numbers in given list
- Python program to find second largest number in a list
- Python program to find smallest number in a list
- Python program to find N largest elements from a list
- Python program to find largest number in a list
- Python program to find middle of a linked list using one traversal
- Python | Make pair from two list such that elements are not same in pairs
- Python program to create a list of tuples from given list having number and its cube in each tuple
- Python | Triple list difference
- Python | Set Difference in list of dictionaries
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.