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] <= 1000class Solution {
public:
bool uniqueOccurrences(vector<int>& arr) {
unordered_map <int, int> m1, m2;
for(auto e: arr)
m1[e]++;
for(auto [K, V]: m1)
if(!m2[V])
m2[V]=K;
else return false;
return true;
}
};
// class Solution {
// public:
// bool uniqueOccurrences(vector<int>& arr) {
// unordered_map <int, int> m;
// unordered_set <int> s;
// for(auto e: arr)
// m[e]++;
// for(auto e: m)
// s.insert(e.second);
// return m.size()==s.size();
// }
// };