729 - The Hamming Distance Problem

#include <cstdio>#include <algorithm>using namespace std;int main(){//freopen("data.in","r",stdin);int T;scanf("%d",&T);while(T--){int h,n;scanf("%d %d",&h,&n);char str[20];int i;for(i=0;i<h-n;i++)str[i]='0';for(;i<h;i++)str[i]='1';str[i]=0;do{printf("%s\n",str);}while(next_permutation(str,str+i));if(T)printf("\n");}return 0;}