poj 2956 Repeatless Numbers

#include<cstdio>#include<cstring>#include<algorithm>using namespace std;struct data{    int v,s;    data(){}    data(int _v,int _s){v=_v,s=_s;}}po[1001000];int main(){    int f,r;    f=1;    for(r=1;r<10;r++)        po[r]=data(r,1<<r);    while(r<=1000000)    {        int v=po[f].v,s=po[f].s;        f++;        for(int i=0;i<10;i++) if(!(s&(1<<i)))     po[r++]=data(v*10+i,s|(1<<i));    }    int n;    while(scanf("%d",&n),n)    {        printf("%dn",po[n].v);    }    return 0;}