leetcode

0 class Solution {

1 public:

2 int firstMissingPositive(vector<int> &nums) const {

3 const int n = size(nums);

4 for (int i = 0; i < n; i++)

5 if (nums[i] <= 0) nums[i] = n + 1;

6 for (int i = 0; i < n; i++) {

7 const int num = abs(nums[i]);

8 if (num <= n) nums[num - 1] = -abs(nums[num - 1]);

9 }

10 for (int i = 0; i < n; i++)

11 if (nums[i] > 0) return i + 1;

12 return n + 1;

13 }

14 };