LeetCode(77) Combinations

哎，花了这么长时间，竟然是因为reverse函数掌握不够透彻，他改变了操作数，我竟然全然没想注意到这一变化。哎╮(╯▽╰)╭,眼睛都花了。男人嘛，保重，自强，O(∩_∩)O哈哈~

代码如下：

class Solution {
public:

    void dfs(vector<int> &nums,  int index, int depth, int k, vector<int> &tmpVectorint, vector<vector<int>> &result) {

        if(depth == k) {

                return;

        }


        if(nums.size() - index < k - depth)

            return;

        for(int i = index; i < nums.size(); i++) {

            tmpVectorint[depth] = nums[i];
            if(depth == k - 1) {
                //缺少这个步骤让我在这道题上花费好多时间。哎╮(╯▽╰)╭
                vector<int> tmp(tmpVectorint.begin(), tmpVectorint.end());
                reverse(tmp.begin(), tmp.end());
                cout << tmp[0] << endl;
                cout << tmp[1] << endl;
                result.push_back(tmp);

                continue;

            }

            dfs(nums, i + 1, depth + 1, k, tmpVectorint, result);

        }

    }

    vector<vector<int>> combine(int n, int k) {

        vector<int> nums;
        for(int i = n; i > 0; i--) 

            nums.push_back(i);

        vector<vector<int>> result;
        vector<int> tmpVectorint(k, 0);

        dfs(nums, 0, 0, k, tmpVectorint, result);

        reverse(result.begin(), result.end());

        return result;

    }
};