[Algo Rhythm🕺💃] LeetCode - Number of Good Pairs

📚 Problem description

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

 

🎯 My code

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

 

🧐 Why I wrote that code

To call a pair (i, j) as 'good', we need to check two conditions.

One is whether i is greater than j, and the other is whether nums[i] is equal to nums[j].

 

Using brute force algorithm, whenever I and j meets two condition, increment number!

 

📖 What I learned

It was just simple brute force algorithm. Nothing special😃