原题
Description Given a positive integer n, write a program to find out a nonzero multiple m of n whose decimal representation contains only the digits 0 and 1. You may assume that n is not greater than 200 and there is a corresponding m containing no more than 100 decimal digits. Input The input file may contain multiple test cases. Each line contains a value of n (1 <= n <= 200). A line containing a zero terminates the input. Output For each value of n in the input print a line containing the corresponding value of m. The decimal representation of m must not contain more than 100 digits. If there are multiple solutions for a given value of n, any one of them is acceptable. Sample Input 2 6 19 0 Sample Output 10 100100100100100100 111111111111111111
思路解析 寻找能整除N的，由0,1组成的数。
AC代码
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; bool vis; int n; void dfs(unsigned __int64 x,int n,int k){ if(vis) return; if(x%n==0){ printf("%I64u\n",x); vis=true; return; } if(k==19) return; dfs(x*10,n,k+1); dfs(x*10+1,n,k+1); } int main(){ while(scanf("%d",&n)){ if(n==0) break; vis=false; dfs(1,n,0); } return 0; }