Given an array A[] of size N and a number x. count all the pairs in array such that A*^A[j]=x.

**DON’T PROPOSE THE SOLUTIONS WITH O(N^2) AND ALSO THE SOLUTION GIVEN ON GEEKSFORGEEKS**

**THIS IS THE SOLUTION PROVIDED BY CODEFORCES**

Note that if then . Keep in numx the number of repetitions of number x. Now for each x, add to answer. Then divide answer by 2 (if X is 0, don’t).

Time complexity: O(n).

Corner case #1 : Some codes got WA when X is 0.

Corner case #2 : Some codes got RE because can be as large as max(x, y)·2.

**I couldn’t understand this solution please explain this one or some other approach.**