STL之全排列函数poj1716

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

using namespace std;

int main(){

    //freopen("input.txt","r",stdin);

    int a[5],tag=0;
    while(scanf("%d%d%d%d",&a[0],&a[1],&a[2],&a[3])){
        if(a[0]==0 && a[1]==0 && a[2]==0 && a[3]==0)
            break;
        if(tag)
            printf("\n");
        tag=1;
        int flag=1,tmp;
        do{
            if(a[0]==0)
                continue;
            if(flag){
                printf("%d%d%d%d",a[0],a[1],a[2],a[3]);
                flag=0;
            }else if(tmp==a[0])
                printf(" %d%d%d%d",a[0],a[1],a[2],a[3]);
            else
                printf("\n%d%d%d%d",a[0],a[1],a[2],a[3]);
            tmp=a[0];
        }while(next_permutation(a,a+4));
        printf("\n");
    }
    return 0;
}