Unique Number of Occurrences Problem & Solution

See the unique number of occurrences problem on LeetCode.

C++ Solution

#pragma GCC optimize("Ofast")
#pragma GCC optimization("unroll-loops")
#pragma GCC target("avx,avx2,fma")

static const int _=[](){ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();

class Solution {
  bool uniqueOccurrences(vector<int>& arr) {
    unordered_map<int, int> freq;
    for (auto v : arr) {

    unordered_set<int> unique;
    for (auto [k, v] : freq) {

    return freq.size() == unique.size();

Start Here

Many Paths. Follow Yours.