zoj1889

Ones

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Time Limit: 2 Seconds      Memory Limit: 65536 KB

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Given any integer 0 <= n <= 10000 not divisible by 2 or 5, some multiple of n is a number which in decimal notation is a sequence of 1's. How many digits are in the smallest such a multiple of n?

Sample Input

3 
7 
9901

Sample Output

3
6
12

#include<iostream>#include<stdio.h>#include<string.h>#include<algorithm>using namespace std;int solve(int n){int x=1;    //代表数字111……对n取模后的余数 for(int i=1;;i++){if(x%n==0)return i;     //直到余数变为0 x=(x*10+1)%n;       //长度每增加一位余数变化 }}int main(){int n;while(~scanf("%d",&n)){printf("%d\n",solve(n));}}