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Unique Number of Occurrences

Problem statement​

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: trueExplanation: 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

My solution​

/**
 * @param {number[]} arr
 * @return {boolean}
 */
var uniqueOccurrences = function(arr) {
    const map = new Map()
    
    for (const num of arr) {
        if (!map.has(num)) {
            map.set(num, 0)
        }
        
        map.set(num, map.get(num) + 1)
    }
    
    const set = new Set();
    
    for (const value of map.values()) {
        if (set.has(value)) {
            return false
        }
        set.add(value)
    }
    
    return true;
    
    
};