[Java] BOJ 1986 체스

 

1986번: 체스

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정답 코드

• 퀸 / 나이트 / 폰의 위치를 2차원 배열에 저장하기
• 퀸 / 나이트의 방문 가능한 위치 확인
• 퀸 8방향 직선이동 (장애물 만날시 멈춤)
• 나이트 8방향 대각선 이동 (장애물 있어도 건너뜀)

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

public class Main {

    static BufferedReader br;
    static BufferedWriter bw;
    static StringTokenizer st;
    static int N, M;
    static char[][] arr;
    static boolean[][] visit;
    static int[] qx = { 0, 1, 1, 1, 0, -1, -1, -1 };
    static int[] qy = { -1, -1, 0, 1, 1, 1, 0, -1 };
    static int[] kx = { 1, 2, 2, 1, -1, -2, -2, -1 };
    static int[] ky = { -2, -1, 1, 2, 2, 1, -1, -2 };

    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));
        bw = new BufferedWriter(new OutputStreamWriter(System.out));

        st = new StringTokenizer(br.readLine(), " ");
        N = Integer.parseInt(st.nextToken());
        M = Integer.parseInt(st.nextToken());

        arr = new char[N][M];
        visit = new boolean[N][M];

        for (int tc = 0; tc < 3; tc++) {
            st = new StringTokenizer(br.readLine(), " ");
            char horse;
            if (tc == 0) {
                horse = 'Q';
            } else if (tc == 1) {
                horse = 'K';
            } else {
                horse = 'P';
            }
            int cnt = Integer.parseInt(st.nextToken());
            for (int i = 0; i < cnt; i++) {
                int r = Integer.parseInt(st.nextToken()) - 1;
                int c = Integer.parseInt(st.nextToken()) - 1;
                arr[r][c] = horse;
                visit[r][c] = true;
            }
        }

        for (int i = 0; i < N; i++) {
            for (int j = 0; j < M; j++) {
                if (arr[i][j] == 'Q') {
                    moveQ(i, j);
                } else if (arr[i][j] == 'K') {
                    moveK(i, j);
                }
            }
        }

        System.out.println(cnt());
    }

    private static void moveK(int y, int x) {
        for (int dic = 0; dic < 8; dic++) {
            int nx = x + kx[dic];
            int ny = y + ky[dic];

            if (nx < 0 || ny < 0 || nx >= M || ny >= N) {
                continue;
            }
            visit[ny][nx] = true;
        }
    }

    private static void moveQ(int y, int x) {
        for (int dic = 0; dic < 8; dic++) {

            int nx = x + qx[dic];
            int ny = y + qy[dic];
            while (true) {
                if (nx < 0 || ny < 0 || nx >= M || ny >= N) {
                    break;
                }

                if (Character.isAlphabetic(arr[ny][nx])) {
                    break;
                }
                visit[ny][nx] = true;
                nx += qx[dic];
                ny += qy[dic];
            }
        }
    }

    private static int cnt() {
        int sum = 0;
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < M; j++) {
                if (!visit[i][j]) {
                    sum++;
                }
            }
        }
        return sum;
    }
}