[kuangbin带你飞]专题一 简单搜索 E - Find The Multiple

E -  Find The Multiple

Time Limit:1000MS     Memory Limit:10000KB     64bit IO Format:%I64d & %I64u

Submit  Status  Practice  POJ 1426

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

分析：bfs搜索，没有剪枝，若不是有题目分类，应该猜不到是搜索。。但理解一下也确实搜索是个好方法，两条分之‘0’，‘1’。

c++提交tle，g++提交ac

code：

#include <cstdio>
#include <iostream>
#include <queue>

using namespace std;
typedef unsigned long long ll;
ll a,ans;

void bfs()
{
    ans=1;
    queue <ll> q;q.push(ans);
    
    while(q.size())
    {
        ll now=q.front();
        q.pop();
        
        if( !(now%a) )
        {
            printf("%lld\n",now);
            return ;
        }
        
        ll ne1=now*10+1,ne0=now*10;
        q.push(ne1);
        q.push(ne0);
    }
}
int main(void)
{
    while(scanf("%lld",&a)&&a)
    {
        bfs();
    }
}