1207. Unique Number of Occurrences

Unique Number of Occurrences

Problem Description

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

Let`s code it!

/**
 * @param {number[]} arr
 * @return {boolean}
 */
var uniqueOccurrences = function(arr) {
    let hash = {};
    let occurrences = new Set();
    for(let i=0;i<arr.length;i++){
        if(hash[arr[i]] != undefined){
             hash[arr[i]] += 1;
        }else{
            hash[arr[i]] = 1;
        }
    }
    
    for(let count in hash){
        if(occurrences.has(hash[count])){
            return false;
        }
        occurrences.add(hash[count])
    }
    return true;
};

Conclusion

That’s all folks! In this post, we solved LeetCode problem #1207. Unique Number of Occurrences

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You can find the complete source code on my GitHub repository. If you like what you learn. feel free to fork 🔪 and star ⭐ it.

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Happy coding!