【HDOJ】1180 诡异的楼梯
bfs+优先队列。wa了N次，才发现可以停留等待楼梯变换方向。
1 #include <iostream> 2 #include <queue> 3 #include <cstdio> 4 #include <cstring> 5 using namespace std; 6 7 #define MAXNUM 55 8 9 typedef struct node_st { 10 int x, y, t; 11 node_st() {} 12 node_st(int xx, int yy, int tt) { 13 x = xx; y = yy; t = tt; 14 } 15 friend bool operator < (node_st a, node_st b) { 16 return a.t > b.t; 17 } 18 } node_st; 19 20 char map[MAXNUM][MAXNUM]; 21 char visit[MAXNUM][MAXNUM]; 22 int n, m; 23 int begx, begy, endx, endy; 24 int direct[4][2] = {{1,0},{-1,0},{0,1},{0,-1}}; 25 26 int bfs(int begx, int begy) { 27 priority_queue<node_st> que; 28 node_st node; 29 int i, x, y, nx, ny, t; 30 31 que.push(node_st(begx, begy, 0)); 32 memset(visit, 0, sizeof(visit)); 33 visit[begx][begy] = 1; 34 35 while ( !que.empty() ) { 36 node = que.top(); 37 if (map[node.x][node.y] == 'T') { 38 return node.t; 39 } 40 que.pop(); 41 for (i=0; i<4; ++i) { 42 x = node.x + direct[i][0]; 43 y = node.y + direct[i][1]; 44 if (x<0 || x>=n || y<0 || y>=m) 45 continue; 46 if (visit[x][y] || map[x][y] == '*') 47 continue; 48 if (map[x][y] == '.' || map[x][y]=='T') { 49 que.push(node_st(x,y,node.t+1)); 50 visit[x][y] = 1; 51 continue; 52 } 53 if (map[x][y]=='|' || map[x][y]=='-') { 54 nx = x + direct[i][0]; 55 ny = y + direct[i][1]; 56 t = node.t + 1; 57 if (nx<0 || nx>=n || ny<0 || ny>=m) 58 continue; 59 if (visit[nx][ny] || map[nx][ny]=='*') 60 continue; 61 if ( ((map[x][y]=='|') && ((node.t&1)==0) && (i==2||i==3)) || 62 ((map[x][y]=='|') && ((node.t&1)!=0) && (i==0||i==1)) || 63 ((map[x][y]=='-') && ((node.t&1)==0) && (i==0||i==1)) || 64 ((map[x][y]=='-') && ((node.t&1)!=0) && (i==2||i==3)) ) 65 ++t; 66 visit[nx][ny] = 1; 67 que.push(node_st(nx, ny, t)); 68 } 69 } 70 } 71 72 return -1; 73 } 74 75 int main() { 76 int i, j; 77 78 while (scanf("%d %d%*c",&n,&m) != EOF) { 79 for (i=0; i<n; ++i) { 80 scanf("%s", map[i]); 81 for (j=0; j<m; ++j) { 82 if (map[i][j] == 'S') { 83 begx = i; 84 begy = j; 85 } 86 } 87 } 88 i = bfs(begx, begy); 89 printf("%d\n", i); 90 } 91 92 return 0; 93 }
