First Missing Positive.txt

class Solution {
public:
    int firstMissingPositive(int A[], int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        for (int i = 0; i < n; i++)
            while ((A[i] > 0) && (A[i] <= n) && (A[A[i]-1] != A[i])) {
                int t = A[A[i]-1];
                A[A[i]-1] = A[i];
                A[i] = t;
            }
        int j = 0;
        while ((j < n) && (A[j] == j+1))
            j++;
        return j+1;
    }
};