题解 | #没有重复项数字的全排列#

#include <map>
#include <vector>
class Solution {
private:
    vector<int> tmp;
    vector<vector<int>> res;
public:
    void permuteHelper(vector<int>& num, vector<bool>& used){
        if (tmp.size() == num.size()) {
            res.push_back(tmp);
            return;
        }     
        for (int i = 0; i < num.size(); i++) {
            if (used[i]) {
                continue;
            }
            used[i] = true;
            tmp.push_back(num[i]);
            permuteHelper(num, used);
            used[i] = false;
            tmp.pop_back();
        }
    }
    /**
     * 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) {
        // write code here
        vector<bool> used(num.size(), false);
        permuteHelper(num, used);
        return res;
    }
};