【洛谷】P1605 - 迷宫

public class Main {
    static int N ;
    static int M ;
    static int T ;
    static int[][] area ;
    static int SX ;
    static int SY ;
    static int EX ;
    static int EY ;
    
    static int[] ZhX ;
    static int[] ZhY ;
    
    static int count ;
    
    static int[] px = {-1, 1 , 0 , 0};
    static int[] py = {0 , 0 , -1, 1};
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        N = sc.nextInt();
        M = sc.nextInt();
        T = sc.nextInt();
        
        SX = sc.nextInt();
        SY = sc.nextInt();
        EX = sc.nextInt();
        EY = sc.nextInt();
        
        area = new int[N][M];
        ZhX = new int[T];
        ZhY = new int[T];
        
        count = 0;
        
        for (int i = 0; i < T; i++) {
            ZhX[i] = sc.nextInt();
            ZhY[i] = sc.nextInt();
        }
        
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < M; j++) {
                area[i][j] = 0;
            }
        }
        
        for (int i = 0; i < T; i++) {
            int r = ZhX[i]-1;
            int c = ZhY[i]-1;
            area[r][c] = 2; // 障碍物处 
        }
        
        area[SX-1][SY-1] = 1;
        DFS(SX-1 , SY-1);
        
        System.out.println(count);
        
        
    }

    public static void DFS(int x, int y) {
        if (x == (EX-1) && y == (EY-1)) {
            count += 1;
            return;
        }
        
        if (area[x][y] == 2 ) {
            return;
        }
        
        for (int i = 0; i != 4; i++) {
            int newx = x + px[i];
            int newy = y + py[i];
            if (newx >= 0 && newx < N && newy >= 0 && newy < N && area[newx][newy] == 0) {
                area[newx][newy] = 1;
                DFS(newx,newy);
                area[newx][newy] = 0;
            }
            
        }
        
        
    }
}