usaco hamming

#include<stdio.h>int n,b,d,a[70]; int cmp(int u,int v){    int k=0;    while (u>0 || v>0) {        if (u%2!=v%2) k++;        u=u/2;v=v/2;    }    if (k>=d) return 1;else return 0;}int main(){freopen("hamming.in","r",stdin);freopen("hamming.out","w",stdout);int i,j,f;scanf("%d%d%d",&n,&b,&d);    a[1]=0;    for (i=2;i<=n;i++) {        a[i]=a[i-1]+1;        do {            f=1;            for (j=1;j<i;j++) {                if (!cmp(a[i],a[j])) {f=0;break;}            }            if (f) break;            a[i]++;        } while (1);    }    for (i=1;i<=n;i++)        if (i%10==0 || i==n) printf("%d\n",a[i]); else printf("%d ",a[i]);return 0;}