Question

How to choose k elements from an array such that their sum is s ?

Answer 1

Answer:

Given an integer array and a positive integer k, count all distinct pairs with difference equal to k.

Examples:

Input: arr[] = {1, 5, 3, 4, 2}, k = 3

Output: 2

There are 2 pairs with difference 3, the pairs are {1, 4} and {5, 2}

Input: arr[] = {8, 12, 16, 4, 0, 20}, k = 4

Output: 5

There are 5 pairs with difference 4, the pairs are {0, 4}, {4, 8},

{8, 12}, {12, 16} and {16, 20}