[SWEA] 2806. N-Queen - JAVA

문제

https://swexpertacademy.com/main/code/problem/problemDetail.do?contestProbId=AV7GKs06AU0DFAXB 

SW Expert Academy

풀이

이전에 백준에서 푼 문제. 풀이는 밑 링크에 가면 있다.

https://hse06028.tistory.com/202

코드

import java.util.*;
import java.io.*;

public class Main {
	
	static int n;
	static int result = 0;
	static boolean up[];
	static boolean downcross[];
	static boolean upcross[];
	
	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
				
		int T = Integer.parseInt(br.readLine());
		for(int test_case = 1; test_case <= T; test_case++)
		{			
			n = Integer.parseInt(br.readLine());
			up = new boolean [n];
			downcross = new boolean [2*n -1];
			upcross = new boolean [2*n -1];
			
			queen(0);
			
			System.out.println("#"+test_case+" "+result);

		}
		
	}
	
	static void queen(int cnt) {
		if(cnt == n) {
			result++;
			return;
		}
		
		for(int i=0;i<n;i++) {
			if(!up[i] && !upcross[cnt+i] && !downcross[cnt - i + n - 1]) {
				up[i] = true;
				upcross[cnt+i] = true;
				downcross[cnt - i + n - 1] = true;
			
				queen(cnt+1);
				
				up[i] = false;
				upcross[cnt+i] = false;
				downcross[cnt - i + n - 1] = false;
				
			}
			
		}
		
	}
	
}