dfs求全排列模板

#include<iostream>#define N 5 //当N等于5求1-5全排列 using namespace std;string ans(N, '0');//这里为了方便用了字符串类型int book[N+1]={0};int dfs(int step){    if(step>N)    {        cout<<ans;        cout<<endl;        return 0;    }    for(int i=1;i<=N;i++)    {        if(book[i]==0)        {            ans[step-1]='0'+i;            book[i]=1;            dfs(step+1);            book[i]=0;        }    }    return 0;} int main(){    dfs(1);    return 0;}