1 #include<iostream>
2 #include<queue>
3 using namespace std;
4 const int INF = 100000000;
5 const int maxn = 10000;
6 typedef pair<int, int> P; //储存坐标下x,y
7 int maze[maxn][maxn];
8 int d[maxn][maxn]; //储存每个坐标的最短路径
9 int sx, sy; //起始坐标
10 int ex, ey; //终点坐标
11 int dx[4] = { 1,0,-1,0 };
12 int dy[4] = { 0,1,0,-1 };
13 int bfs()
14 {
15 queue<P> que; //bfs用队列
16 for (int i = 0; i < maxn; i++) { //初始化所有距离为极大
17 for (int j = 0; j < maxn; j++) {
18 d[i][j] = INF;
19 }
20 }
21 que.push(P(sx, sy));
22 d[sx][sy] = 0;
23 while (que.size()) {
24 P p = que.front();
25 que.pop();
26 if (p.first == ex && p.second == ey)
27 break;
28 for (int i = 0; i < 4; i++) {
29 int nx = p.first + dx[i];
30 int ny = p.second + dy[i];
31 if (nx >= 0 && nx < N && ny >= 0 && ny < N && d[nx][ny] == INF && maze[nx][ny] == ) {
32 que.push(P(nx, ny));
33 d[nx][ny] = d[p.first][p.second] + 1;
34 }
35 }
36 }
37 return d[ex][ey];
38 }
