题目：

题解：

class Solution {
public:vector<int> findDisappearedNumbers(vector<int>& nums) {int n = nums.size();for (auto& num : nums) {int x = (num - 1) % n;nums[x] += n;}vector<int> ret;for (int i = 0; i < n; i++) {if (nums[i] <= n) {ret.push_back(i + 1);}}return ret;}
};