1207. Unique Number of Occurrences - easy
문제
Given an array of integers arr, write a function that returns true if and only if the number of occurrences of each value in the array is unique.
제한사항
- 1 <= arr.length <= 1000
- -1000 <= arr[i] <= 1000
입출력 예
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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
풀이
- Hash
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class Solution {
public:
bool uniqueOccurrences(vector<int>& arr) {
map<int, int> m;
set<int> s;
for(auto& i : arr){
++m[i];
}
for(auto i = m.begin() ; i != m.end() ; ++i){
s.insert(i->second);
}
return s.size() == m.size();
}
};