字典序

#include<iostream>

#include<algorithm>

#include<string.h>

int a[6],n;

bool b[6];

using namespace std;

int main()

{

    voidpp(int);

    while(cin>>n)

    {

        memset(b,false,sizeof(b));

        memset(a,0,sizeof(a));

        pp(1);

    }

    return0;

}

void pp(int k)

{

    for(inti=1;i<=n;i++)

    {

        if(b[i]==false)

        {

            a[k]=i;b[i]=true;

            if(k==n)

            {

                for(intj=1;j<=n;j++)

                {

                    if(j==n) cout<<a[j]<<endl;

                    elsecout<<a[j]<<' ';

                }

                b[i]=false;return;

            }

            pp(k+1);

            b[i]=false;

        }

    }

}