[백준 / Java] 1010번

https://www.acmicpc.net/problem/1010

1010번: 다리 놓기

 

import java.util.Scanner;

public class Main {
	
	static int combination(int N, int M) {
		//mCn=m*(m-1)*...(m-n+1)/n*(n-1)*(n-2)...1
			double a = 1.0;
			for(int i=0; i<N; i++) {
				a *=(double)(M-i)/(N-i); 
			}
		return (int)Math.round(a);
	}
	 public static void main(String[] args) {
		 
		 Scanner scan = new Scanner(System.in);
		 int T = scan.nextInt();
			for(int i = 0; i < T; i++) {
				int N = scan.nextInt();			
				int M = scan.nextInt();
				System.out.println(combination(N,M));
				}
			    }	
			}