POJ 题目1426 Find The Multiple（DFS）

Find The Multiple

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

Source

Dhaka 2002

题目描述的100位，吓了一跳，以为是大数，看别人代码才知道这个题实际上不会超过unsigned  __int64,题目大意是找一个数m是n的倍数，m只由0和1组成，和样例的输出不一样也过了

ac代码

#include<stdio.h>
#include<string.h>
int n,m;
int flag;
void dfs(unsigned __int64 num,int k)
{
	if(flag==1||k==19)
		return;
	if(num%n==0)
	{
		printf("%I64u\n",num);
		flag=1;
		return;
	}
	dfs(num*10,k+1);
	dfs(num*10+1,k+1);
}
int main()
{
	while(scanf("%d",&n)!=EOF,n)
	{
		flag=0;
		dfs(1,0);
	}
}