Problem:
Score : 700 points

Problem Statement

Find the smallest possible sum of the digits in the decimal notation of a positive multiple of K.

Constraints

2 \leq K \leq 10^5

K is an integer.

Input

Input is given from Standard Input in the following format:

K

Output

Print the smallest possible sum of the digits in the decimal notation of a positive multiple of K.

Sample Input 1

6

Sample Output 1

3

12=6×2 yields the smallest sum.

Sample Input 2

41

Sample Output 2

5

11111=41×271 yields the smallest sum.

Sample Input 3

79992

Sample Output 3

36

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
#define ll long long
#define met(a) memset(a,0,sizeof(a))
#define inf 0x3f3f3f3f
using namespace std;
const int mod=1e9+7;
const int N=1e6+10;
int a[600];
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll i,j,k,m,n;
    ll ans=0,cnt=9999999999;
    cin>>k;
    for(i=1; i<=100000; i++)
    {
        ans=0;
        m=k*i;
        while(m>0)
        {
            ans+=(m%10);
            m/=10;
        }
        cnt=min(cnt,ans);
    }
    cout<<cnt<<endl;
    return 0;
}