HDU 2117 Just a Numble

http://acm.hdu.edu.cn/showproblem.php?pid=2117

Problem Description

Now give you two integers n m, you just tell me the m-th number after radix point in 1/n,for example n=4,the first numble after point is 2,the second is 5,and all 0 followed

 

Input

Each line of input will contain a pair of integers for n and m(1<=n<=10^7,1<=m<=10^5)

 

Output

For each line of input, your program should print a numble on a line,according to the above rules

 

Sample Input

4 2

5 7

123 123

 

Sample Output

5

0

8

 

时间复杂度：$O(m)$

代码：

#include <bits/stdc++.h>
using namespace std;

int main() {
    int n, m, sum, k;
    while(~scanf("%d%d", &n, &m)) {
        sum = 1;
        for(int i = 0; i < m; i ++) {
            sum = sum * 10;
            k = sum / n;
            sum = sum % n;
        }
        printf("%d\n",k % 10);
    }
    return 0;
}