Introduction

So here we are given an array. We have have to find how many pairs have the equal value like, nums = [1,2,3,1,1,3] and There are 4 good pairs (0,3), (0,4), (3,4), (2,5) 0-indexed.

Examples

Steps

1. Take a nested for loop
2. 1st loop runs 0 to nums.length.
3. 2nd loop starts from first loop index+1 and ends to nums.length.
4. if (nums[i] == nums[j]), counter++
5. return counter.

JavaCode

class Solution {
    public int numIdenticalPairs(int[] nums) {
        int counter = 0;
        for(int i =0; i<nums.length; i++){
            for(int j = i+1; j<nums.length; j++){
                if( nums[i] == nums[j]){
                    counter++;
                }
            }
        }
        return counter;
    }
}

Output