题解

c++

#include <iostream>
#include <cstring>
using namespace std;

int n, m, sx, sy, fx, fy, vis[1010][1010], nx[4] = {0,0,1,-1}, ny[4] = {1,-1,0,0};
char a[1010][1010];

void dfs(int x, int y) {
    vis[x][y] = 1;
    for (int i = 0; i < 4; i++) {
        int xx = x + nx[i], yy = y + ny[i];
        if (xx >= 1 && xx <= n && yy >= 1 && yy <= m && vis[xx][yy] == -1 && a[xx][yy] != '#') dfs(xx,yy);
    }
}

int main () {
    memset(vis, -1, sizeof vis);
    scanf("%d %d\n%d %d %d %d\n", &n, &m, &sx, &sy, &fx, &fy);
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            scanf("%c", &a[i][j]);
        }
        scanf("\n");
    }
    dfs(sx,sy);
    if (vis[fx][fy] != -1) cout << "YES";
    else cout << "NO";
    return 0;
}