(dfs) acwing 842. Arrange numbers

842. Arrange numbers

Topic link https://www.acwing.com/problem/content/844/
subject ：

Method 1 ：dfs

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
bool vis[10];
int a[10];
int n;
void dfs(int u,int id){
    
    a[++id]=u;
    if(id==n){
    
        for(int i=1;i<=n;i++){
    
            printf("%d ",a[i]);
        }
        printf("\n");
        return ;
    }
    vis[u]=1;
    for(int i=1;i<=n;i++){
    
        if(!vis[i]) dfs(i,id);
    }
    vis[u]=0;
}
int main(){
    
    cin>>n;
    for(int i=1;i<=n;i++){
    
        memset(vis,0,sizeof vis);
        dfs(i,0);
    }

    return 0;
}

next_permutation Method https://blog.csdn.net/weixin_46028214/article/details/115432647