求调

#include <bits/stdc++.h>
#define PII pair<int, int>
using namespace std;

int n;
const int N = 1005;
int sx, sy, fx, fy;
char g[N][N];
int st[N][N], dis[N][N];
int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, 1, 0, -1};

void bfs (int x, int y) {
	queue<PII> w;
	w.push({x, y});
	st[x][y] = 1;
	while (w.size()) {
		auto t = w.front();
		w.pop();
		if (t.first == fx && t.second == fy) {
			cout << dis[t.first][t.second] << endl;
			return;
		}
		for (int i = 0; i < 4; i++) {
			int tx = t.first + dx[i];
			int ty = t.second + dy[i];
			if (tx >= 1 && tx <= n && ty >= 1 && ty <= n && g[tx][ty] == 0 && st[tx][ty] == 0) {
				st[tx][ty] = 1;
				dis[tx][ty] = dis[t.first][t.second] + 1;
				w.push({tx, ty});
			}
		}
	}
	return;
}

int main () {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			cin >> g[i][j];
		}
	}
	cin >> sx >> sy >> fx >> fy;
	bfs (sx, sy);
	return 0;
}