双题解

深搜：

#include <bits/stdc++.h>
using namespace std;
int n, m, sx, sy, fx, fy;
char mp[50][50];
int vis[30][30];
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, -1, 1};
bool flag = 0;
void dfs (int x, int y) {
    if (x == fx && y == fy) {
        flag = 1;
        return;
    }
    for (int i = 0;i < 4;i++) {
        int nx = dx[i] + x;
        int ny = dy[i] + y;
        if (nx >= 1 && nx <= n && ny >= 1 && ny <= m && vis[nx][ny] == 0 && mp[nx][ny] == '.' ) {
            vis[nx][ny] = 1;
            dfs(nx, ny);
            vis[nx][ny] = 0;
        }
    }
}
int main () {
    cin >> n >> m >> sx >> sy >> fx >> fy;
    for (int i = 1;i <= n;i++) {
        for (int j = 1;j <= m;j++) {
            cin >> mp[i][j];
        }
    }
    vis[sx][sy] = 1;
    dfs(sx, sy);
    if (flag) cout << "YES";
    else cout << "NO";
    return 0;
}

广搜：

#include <bits/stdc++.h>
using namespace std;
int n, m, sx, sy, fx, fy;
char mp[50][50];
int vis[50][50];
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, -1, 1};
struct node {
	int x, y;
};
int main () {
    cin >> n >> m >> sx >> sy >> fx >> fy;
    for (int i = 1;i <= n;i++) {
        for (int j = 1;j <= m;j++) {
            cin >> mp[i][j];
        }
    }
    queue <node> q;
    q.push({sx, sy});
    vis[sx][sy] = 1;
    while (q.size() > 0) {
    	node f = q.front();
    	q.pop();
    	for (int i = 0;i < 4;i++) {
    		int nx = dx[i] + f.x;
    		int ny = dy[i] + f.y;
    		if (nx >= 1 && nx <= n && ny >= 1 && ny <= m && vis[nx][ny] == 0 && mp[nx][ny] == '.' ) {
    			vis[nx][ny] = 1;
				q.push({nx, ny});
    		}
		}
		if (f.x == fx && f.y == fy) {
			cout << "YES";
			return 0;
		}
	}
	cout << "NO";
    return 0;
}