백준 9184번

원본 : www.acmicpc.net/problem/9184

9184번: 신나는 함수 실행

 

풀이

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;

public class Main {
    
    public static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    public static BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
    
    public static void main(String[] args) throws Exception {
        
        int result[][][] = new int[21][21][21];
        
        ArrayList<String> list = new ArrayList<String>();
        while(true) {
            String str = reader.readLine();
            if (str.equals("-1 -1 -1")) {
                break;
            } else {
                int a = Integer.parseInt(str.split(" ")[0]);
                int b = Integer.parseInt(str.split(" ")[1]);
                int c = Integer.parseInt(str.split(" ")[2]);
                list.add("w(" + a + ", " + b + ", " + c + ") = " + w(a, b, c, result));
            }
        }
        
        for (int i = 0; i < list.size(); i++) {
            writer.write(list.get(i) + "\n");
        }
        
        writer.flush();
    }
    
    public static int w(int a, int b, int c, int result[][][]) {
        if (a <= 0 || b <= 0 || c <= 0) {
            return 1;
        } else if (a > 20 || b > 20 || c > 20) {
            return w(20, 20, 20, result);
        } else if (result[a][b][c] == 0) {
            if (a < b && b < c) {
                return result[a][b][c] = w(a, b, c - 1, result) + w(a, b - 1, c - 1, result) - w(a, b - 1, c, result);
            } else {
                return result[a][b][c] = w(a - 1, b, c, result) + w(a - 1, b - 1, c, result) + w(a - 1, b, c - 1, result) - w(a - 1, b - 1, c - 1, result);
            }
        } else {
            return result[a][b][c];
        }
    }
    
}