题解

#include <bits/stdc++.h>
using namespace std;

const int N = 1505;
const int INF = 0x3f3f3f3f;

int n;
int sx, sy, ex, ey;
char a[N][N];
int dist[N][N];
int dx[4] = {1, 1, -1, -1};
int dy[4] = {1, -1, 1, -1};
struct node{
int x,y;
};

void bfs() {
memset(dist, -1, sizeof(dist));
queue<node> q;
dist[sx][sy] = 0;
q.push({sx,sy});
while (!q.empty()) {
node cur = q.front(); q.pop();
int x = cur.x, y = cur.y;
if (x == ex && y == ey) return;
for (int dir = 0; dir < 4; dir++) {
for (int d = 1; ; d++) {
int nx = x + dx[dir] * d, ny = y + dy[dir] * d;
if (nx < 1 || nx > n || ny < 1 || ny > n) break;
if (a[nx][ny] == '#') break;
if(dist[nx][ny]!=-1){
if(dist[nx][ny]<=dist[x][y]) break;
}else{
dist[nx][ny] = dist[x][y] + 1;
q.push({nx, ny});
}

        }
    }
}

}

int main() {
cin >> n >> sx >> sy >> ex >> ey;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
cin >> a[i][j];
}
}
bfs();
cout << dist[ex][ey];
return 0;
}