백준 8단계(2775)

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
 
public class Main {
 
    public static int fibo(int floor, int people) {
        //층이 0층이면 그 층의 사람 리턴
        if(floor <= 0) return people;
        //사람
        else if(people <= 0) return 0;
        
        return fibo(floor - 1, people) + fibo(floor, people - 1);
        //ex floor 2 와 3people라고 가정을 하면
        //fibo(2, 3) = 
        //    fibo(1,3) + fibo(2,2)
        // 즉 fibo(1,3) 또한 = fibo(0,3) + fibo(1,2)
        //이런식으로 계속 내려가면 필요한 값이 나온다, 자세한건 블로그에 사진으로 계시
    
    }
    
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        
        int n = Integer.parseInt(br.readLine());
        while(n > 0) {
            //몇층
            int floor = Integer.parseInt(br.readLine());
            //사람수
            int people = Integer.parseInt(br.readLine());
            
            int result = fibo(floor, people);
            
            bw.write(String.valueOf(result) + "\n");
            n--;
            
        }
        bw.flush();
    }
}