Leetcode 448 Find All Numbers Disappeared in an Array

Leetcode 448 Find All Numbers Disappeared in an Array

#include <vector>
using namespace std;

class Solution {
public:
vector<int> findDisappearedNumbers(vector<int>& nums) {
vector<int> disappear;
vector<int> freq(nums.size());
for (int i = 0; i < nums.size(); i++){
freq[nums[i] - 1] ++;//从1开始
}
for (int i = 0; i < freq.size(); i++){
if (freq[i] == 0)
disappear.push_back(i+1);
}
return disappear;
}
};