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Number of Good Pairs - Array - Easy - LeetCode - MiniTV

Number of Good Pairs - Array - Easy - LeetCode - मिनी टीवी

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

public class Solution {
    public int NumIdenticalPairs(int[] nums) {
        int count = 0;
        var map = new Dictionary<int,int>();
        for(int i=0;i<nums.Length;i++){
            if(map.ContainsKey(nums[i])){                
                count+=map[nums[i]];
                map[nums[i]]++;
            }
            else{
                map.Add(nums[i],1);
            }
        }
        
        return count;
    }
}

 


Time Complexity: O(n)

Space Complexity: O(n)