PairswithdifferenceK.java

// Pairs with difference K
// Send Feedback
// You are given with an array of integers and an integer K. You have to find
// and print the count of all such pairs which have difference K.
// Note: Take absolute difference between the elements of the array.
// Input Format:
// The first line of input contains an integer, that denotes the value of the
// size of the array. Let us denote it with the symbol n.
// The following line contains n space separated integers, that denote the value
// of the elements of the array.
// The following line contains an integer, that denotes the value of K.
// Output format :
// The first and only line of output contains count of all such pairs which have
// an absolute difference of K.
// Constraints :
// 0 <= n <= 10^4
// Time Limit: 1 sec
// Sample Input 1 :
// 4
// 5 1 2 4
// 3
// Sample Output 1 :
// 2
// Explanation
// (5,2) and (1,4) are the possible combinations as their absolute difference is
// 3.
// Sample Input 2 :
// 4
// 4 4 4 4
// 0
// Sample Output 2 :
// 6

import java.util.HashMap;

public class Solution {

    public static int getPairsWithDifferenceK(int arr[], int k) {
        // Write your code here
        HashMap<Integer, Integer> map = new HashMap<>();
        int count = 0;
        for (int i : arr) {
            int difference1 = i - k;
            int difference2 = i + k;
            if (map.containsKey(difference1)) {
                count += map.get(difference1);
            }
            if (map.containsKey(difference2) && k != 0) {
                count += map.get(difference2);
            }
            if (map.containsKey(i)) {
                map.put(i, map.get(i) + 1);
            } else {
                map.put(i, 1);
            }
        }
        for (int i : arr) {

        }
        return count;
    }
}