第一次知道。。原来spfa还可以这样写。。。用pq。。。
只需要直接求拐点即可，数据小想怎么搞就怎么搞
（话说怎么这么裸的最短路都写不出来了233）
1 /************************************************************** 2 Problem: 3393 3 User: rausen 4 Language: C++ 5 Result: Accepted 6 Time:36 ms 7 Memory:1156 kb 8 ****************************************************************/ 9 10 #include <cstdio> 11 #include <cstring> 12 #include <algorithm> 13 #include <queue> 14 15 using namespace std; 16 const int dx[4] = {0, 1, 0, -1}; 17 const int dy[4] = {1, 0, -1, 0}; 18 const int N = 105; 19 const int inf = (int) 1e9; 20 21 struct data { 22 int x, y, to, dis; 23 data() {} 24 data(int _x, int _y, int _t, int _d) : x(_x), y(_y), to(_t), dis(_d) {} 25 26 inline bool operator < (const data &b) const { 27 return dis > b.dis; 28 } 29 }; 30 31 int n, m, ans; 32 int sx, sy, ex, ey; 33 int dis[N][N][4], w[N][N]; 34 priority_queue <data> q; 35 36 inline bool in(int x, int y) { 37 return 1 <= x && x <= n && 1 <= y && y <= m; 38 } 39 40 int main() { 41 int i, j; 42 char ch; 43 scanf("%d%d", &m, &n); 44 for (i = 1; i <= n; ++i) 45 for (j = 1; j <= m; ++j) { 46 ch = getchar(); 47 while (ch != 'C' && ch != '.' && ch != '*') 48 ch = getchar(); 49 if (ch == '*') w[i][j] = 1; 50 if (ch == 'C') 51 if (!sx) sx = i, sy = j; 52 else ex = i, ey = j; 53 } 54 memset(dis, 127 / 3, sizeof(dis)); 55 for (i = 0; i < 4; ++i) { 56 q.push(data(sx, sy, i, 0)); 57 dis[sx][sy][i] = 0; 58 } 59 60 int x, y, k, x1, y1; 61 while (!q.empty()) { 62 x1 = x = q.top().x, y1 = y = q.top().y, k = q.top().to; 63 while (in(x1 += dx[k], y1 += dy[k]) && !w[x1][y1] && dis[x1][y1][k] > dis[x][y][k]) { 64 dis[x1][y1][k] = dis[x][y][k]; 65 q.push(data(x1, y1, k, dis[x][y][k])); 66 } 67 for (i = 0; i < 4; ++i) 68 if (dis[x][y][i] > q.top().dis + 1) { 69 dis[x][y][i] = q.top().dis + 1; 70 q.push(data(x, y, i, dis[x][y][i])); 71 } 72 q.pop(); 73 } 74 for (i = 0, ans = inf; i < 4; ++i) 75 ans = min(ans, dis[ex][ey][i]); 76 printf("%d ", ans); 77 return 0; 78 }