algorithms
코드포스 (codeforces)
코드포스 13A (codeforces 13A)
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Problem - 13A - Codeforces
코드
import java.io.*;
public class CF13A {
static int A;
static long sum;
static String hex;
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
A = Integer.parseInt(br.readLine());
for (int i = 2; i < A; i++) {
sum += sumOfDecimalToBaseN(i, A);
}
int b = A - 2;
long g = gcd(sum, b);
sum /= g; b /= g;
bw.write(sum + "/" + b + "\n");
bw.flush();bw.close();
}
public static long gcd(long a, long b) {
while (b != 0) {
long tmp = a % b;
a = b;
b = tmp;
}
return Math.abs(a);
}
public static long sumOfDecimalToBaseN(int n, int a) {
long ans = 0;
while (a != 0) {
int r = a % n;
ans += r;
a /= n;
}
return ans;
}
}