综合实战：迷宫最短路

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

char maze[105][105];
int dist[105][105];
int dx[4] = {0, 0, 1, -1};   // 四个方向的横坐标增量
int dy[4] = {1, -1, 0, 0};   // 对应的纵坐标增量

int bfs(int sx, int sy, int ex, int ey) {
    memset(dist, -1, sizeof(dist));
    queue<pair<int,int>> q;
    q.push({sx, sy});
    dist[sx][sy] = 0;
    while (!q.empty()) {
        pair<int,int> cur = q.front(); q.pop();
        int x = cur.first, y = cur.second;
        if (x == ex && y == ey) return dist[x][y];  // 到达出口
        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i], ny = y + dy[i];
            if (maze[nx][ny] == '.' && dist[nx][ny] == -1) {
                dist[nx][ny] = dist[x][y] + 1;
                q.push({nx, ny});
            }
        }
    }
    return -1;  // 根本走不到出口
}