algorithms
백준 (BOJ)
(BOJ)백준 2407 (baekjoon 2407)
·
2407번: 조합
코드
import java.io.*;
import java.math.BigInteger;
public class B2407 {
static int N, M;
static String in;
static BigInteger[] factorial = new BigInteger[101];
public static void main(String[] args) throws IOException{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
in = br.readLine();
N = Integer.parseInt(in.split(" ")[0]);
M = Integer.parseInt(in.split(" ")[1]);
factorialInit();
BigInteger ans = factorial[N].divide(factorial[M].multiply(factorial[N - M]));
bw.write(ans + "\n");
bw.flush();bw.close();
}
public static void factorialInit() {
factorial[1] = BigInteger.ONE;
for (int i = 2; i < 101; i++) {
factorial[i] = factorial[i - 1].multiply(BigInteger.valueOf(i));
}
}
}