leetcode - Next Permutation

 

class Solution {
public:
    void nextPermutation(vector<int> &num) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        int n = num.size();
        if (n <= 1)
            return;
        int i;
        for (i = n - 2; i >= 0; i--){
            if (num[i]<num[i + 1])
                break;
        }
        if (i < 0){
            sort(num.begin(), num.end());
            return;
        }
        int min = num[i + 1];
        int minIndex = i + 1;
        for (int j = i + 1 + 1; j<n; j++){
            if (num[j]>num[i] && num[j]<min){
                min = num[j];
                minIndex = j;
            }
        }
        int tmp = num[i];
        num[i] = num[minIndex];
        num[minIndex] = tmp;
        sort(&num[i + 1], &num[n]);
    }
};