// 1207. Unique Number of Occurrences

//

// Given an array of integers arr, return true if the number of occurrences of each value in the array is unique or false otherwise.

//

//

//

// 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

//

// Runtime 2 ms Beats 98.18% of users with Java

// Memory 40.18 MB Beats 92.64% of users with Java

class Solution {

public boolean uniqueOccurrences(int[] arr) {

Map<Integer, Integer> occurrences = new HashMap<>();

for (int num: arr) {

occurrences.put(num, occurrences.getOrDefault(num, 0) + 1);

}

Set<Integer> set = new HashSet<>(occurrences.values());

return set.size() == occurrences.size();

}

}