Number of Good Pairs

Number of Good Pairs

Given an array of integers nums.

A pair (i,j) is called good if nums[i] == nums[j] and i < j.

Return the number of good pairs.

Example 1:

Input: nums = [1,2,3,1,1,3]
Output: 4
Explanation: There are 4 good pairs (0,3), (0,4), (3,4), (2,5) 0-indexed.

Example 2:

Input: nums = [1,1,1,1]
Output: 6
Explanation: Each pair in the array are good.

Example 3:

Input: nums = [1,2,3]
Output: 0

Constraints:

• 1 <= nums.length <= 100

• 1 <= nums[i] <= 100

Solutions

🧠 Cpp

class Solution {
public:
    int numIdenticalPairs(vector<int>& nums)
    {
        size_t counter = 0;
        for(auto iter = nums.begin(); iter != nums.end(); ++iter)
            counter += std::count(std::next(iter), nums.end(), *iter);

        return counter;

    }
};