Find The Multiple
Time Limit: 1000MS Memory Limit: 10000K
Total Submissions: 25716 Accepted: 10607 Special Judge
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
题目大意
给出一个整数n，(1 <= n <= 200)。求出任意一个它的倍数m，要求m必须只由十进制的’0’或’1’组成。
/*
0和1 两种状态.
最高位必为1（除1外）.
bfs余数最后状态余数为0
每次扩展front()都会出现两种状态.
然后用BFS跑最优解.
*/
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<queue>
#include<cstring>
#define MAXN 1001
#define LL long long
using namespace std;
int n;
bool b[MAXN];
LL bfs()
{
memset(b,0,sizeof(b));
queue<LL>qq;
qq.push(1);
b[1%n]=true;
while(!qq.empty())
{
LL x=qq.front();
if(x%n==0)
return x;
qq.pop() ;
int xx=x*10%n;
if(!b[xx])
{
qq.push(x*10);
b[xx]=true;
}
int yy=(x*10+1)%n;
if(!b[yy])
{
qq.push(x*10+1);
b[yy]=true;
}
}
}
int main()
{
while(cin>>n)
{
if(!n) break;
printf("%lld\n",bfs());
}
return 0;
}