virtual judge(专题一 简单搜索 E)
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
#include"cstdio" using namespace std; int n; unsigned long long ans; bool flag; void dfs(unsigned long long i,int k) { if(flag) return; //找结果之后就直接返回 if(i%n==0) { flag=true; ans=i; return; } if(k==19) return; //答案在19为之内,无符号long long 可以保存结果 dfs(i*10+0,k+1); dfs(i*10+1,k+1); } int main() { while(scanf("%d",&n)!=EOF&&n!=0) { flag=false; dfs(1,0); printf("%llu ",ans); } return 0; }