[백준] 14888번 / 연산자 끼워넣기 / java

package algorithm;

import java.util.Scanner;

public class Main {
	
	public static int MAX = Integer.MIN_VALUE;	//최댓값
	public static int MIN = Integer.MAX_VALUE;	//최솟값
	public static int N;			//숫자 갯수 
	public static int[] number; 	//숫자
	public static int[] operator = new int[4];	//연산자 개수
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		N = in.nextInt();
		number = new int[N];
		
		//숫자 입력
		for(int i=0;i<N;i++) {
			number[i] = in.nextInt();
		}
		
		//연산자 입력
		for(int i=0;i<4;i++) {
			operator[i] = in.nextInt();
		}
		
		dfs(number[0], 1);
		
		System.out.println(MAX);
		System.out.println(MIN);
	}
	
	public static void dfs(int num, int idx) {
		
		if(idx == N) {
			MAX = Math.max(MAX, num);
			MIN = Math.min(MIN, num);
			return;
		}
		
		for(int i=0;i<4;i++) {
			if(operator[i] > 0 ) {
				
				operator[i]--;
				switch(i) {
					case 0 : dfs(num + number[idx], idx+1); break;
					case 1 : dfs(num - number[idx], idx+1); break;
					case 2 : dfs(num * number[idx], idx+1); break;
					case 3 : dfs(num / number[idx], idx+1); break;
				}
				operator[i]++;
			}
		}
	}
}