POJ--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

#include<string.h>
#include<iostream>
#include<stdio.h>
using namespace std;
typedef long long ll;
int n;
int f;

void dfs(ll x,int k)
{
	if(f)return;
	if(k==19)return;//剪枝
	if(x%n==0)
	{
		cout<<x<<endl;
		f=1;
		return;
	}
	
	
	dfs(x*10,k+1);
	dfs(x*10+1,k+1);
}

int main()
{
	
	while(cin>>n&&n)
	{
		f=0;
		dfs(1,0);//1开始，目前就1位数 
	}
	return 0;
}