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Unique Number of Occurrences - Hash Table - Easy - LeetCode - MiniTV

Unique Number of Occurrences - Hash Table - Easy - LeetCode - मिनी टीवी

Given an array of integers arr, write a function that returns true if and only if the number of occurrences of each value in the array is unique.

Example 1:

Input: arr = [1,2,2,1,1,3]
Output: true
Explanation: The value 1 has 3 occurrences, 2 has 2 and 3 has 1. No two values have the same number of occurrences.
Example 2:

Input: arr = [1,2]
Output: false
Example 3:

Input: arr = [-3,0,1,-3,1,1,1,-3,10,0]
Output: true
 

Constraints:

1 <= arr.length <= 1000
-1000 <= arr[i] <= 1000

public class Solution {
    public bool UniqueOccurrences(int[] arr) {
        var map = new Dictionary<int,int>();
        for(int i=0;i<arr.Length;i++){
            if(map.ContainsKey(arr[i])){
                map[arr[i]]++;
            }
            else{
                map.Add(arr[i],1);
            }
        }
        
        var set = new HashSet<int>();
        foreach(var item in map){
            if(set.Contains(item.Value)){
                return false;
            }
            set.Add(item.Value);
        }
        
        return true;
    }
}

Time Complexity: O(n)

Space Complexity: O(n)