【HDOJ】2612 Find a way
BFS。
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <queue> 5 using namespace std; 6 7 #define INF 0x3fffffff 8 9 typedef struct node_st { 10 int x, y, s; 11 node_st() {} 12 node_st(int xx, int yy, int ss) { 13 x = xx; y = yy; s = ss; 14 } 15 } node_st; 16 17 char visit[205][205]; 18 char map[205][205]; 19 int step[2][205][205]; 20 int n, m; 21 int direct[4][2] = {{-1,0},{1,0},{0,-1},{0,1}}; 22 23 void bfs(int x, int y, int sel) { 24 int i, s; 25 queue<node_st> que; 26 node_st node; 27 28 memset(visit, 0, sizeof(visit)); 29 memset(step[sel], 0, sizeof(step[sel])); 30 visit[x][y] = 1; 31 que.push(node_st(x,y,0)); 32 33 while ( !que.empty() ) { 34 node = que.front(); 35 que.pop(); 36 s = node.s + 1; 37 for (i=0; i<4; ++i) { 38 x = node.x + direct[i][0]; 39 y = node.y + direct[i][1]; 40 if (x<0 || x>=n || y<0 || y>=m) 41 continue; 42 if (visit[x][y]) 43 continue; 44 visit[x][y] = 1; 45 if (map[x][y] == '#') 46 continue; 47 if (map[x][y] == '@') 48 step[sel][x][y] = s; 49 que.push(node_st(x,y,s)); 50 } 51 } 52 } 53 54 int main() { 55 int i, j, tmp, min; 56 int yx, yy, mx, my; 57 58 while (scanf("%d %d%*c", &n, &m) != EOF) { 59 for (i=0; i<n; ++i) { 60 scanf("%s", map[i]); 61 for (j=0; j<m; ++j) { 62 if (map[i][j] == 'Y') { 63 yx = i; 64 yy = j; 65 } else if (map[i][j] == 'M') { 66 mx = i; 67 my = j; 68 } 69 } 70 } 71 bfs(yx, yy, 0); 72 bfs(mx, my, 1); 73 min = INF; 74 for (i=0; i<n; ++i) { 75 for (j=0; j<m; ++j) { 76 if (step[0][i][j] && step[1][i][j]) { 77 tmp = step[0][i][j] + step[1][i][j]; 78 if (tmp < min) 79 min = tmp; 80 } 81 } 82 } 83 printf("%d\n", min*11); 84 } 85 86 return 0; 87 }
