题解 | #没有重复项数字的全排列#

class Solution {
  public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param num int整型vector
     * @return int整型vector<vector<>>
     */
    vector<vector<int> > permute(vector<int>& num) {
        vector<vector<int>> res;
        vector<vector<int>> cur;
        if (num.empty()) return res;
        if (num.size() == 1) res.push_back(num);
        else {
            int elem = num.back();
            num.pop_back();
            cur = permute(num);

            for (int i = 0; i < cur.size(); i++) {
                for (int j = 0; j <= cur.at(i).size(); j++) {
                    vector<int> row = cur.at(i);
                    row.insert(row.begin() + j, elem);
                    res.push_back(row);
                }
            }
        }
        return res;
    }
};

为啥通过了捏？没按顺序来啊