LeetCode 46. Permutations DFS

https://leetcode.com/problems/permutations/

这道题没啥说的 暴力DFS搞，也可以next_permutation

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

const int SIZE = 1000+1;

class Solution {
public:
    vector< vector<int> > permute(vector<int>& nums) {
        vector< vector<int> > ret;
        if(nums.size() == 0) return ret;
        for(int i=0; i<nums.size(); i++)
            vis[i] = false;
        vector <int> gm;
        dfs(nums, gm, ret);
        return ret;
    }

    void dfs(vector <int> &nums, vector <int> gm, vector< vector<int> > &ret ) {
        if(gm.size() == nums.size()) {
            ret.push_back(gm);
            return ;
        }
        for(int i=0;i<nums.size();i++) {
            if( !vis[i] ) {
                vis[i] = 1;
                vector <int> gt(gm);
                gt.push_back(nums[i]);
                dfs(nums,gt,ret);
                vis[i] = 0;
            }
        }
    }

private:
    bool vis[SIZE];
};

int main() {
    //freopen("46.txt", "r", stdin);
    int n, in;
    while( cin >> n ) {
        vector <int> ivec;
        for(int i=0;i<n; i++) {
            cin >> in;
            ivec.push_back(in);
        }
        Solution s;

        vector< vector<int> > ans = s.permute(ivec);
        cout << "ans.size()" << ans.size() << endl;
        for(int i=0;i<ans.size();i++) {
            for(int j=0;j<ans[i].size();j++) {
                cout << ans[i][j] << ", " ;
            }
            cout << endl;
        }
    }
    return 0;
}