poj 3026 brog maze bfs+prim 好坑爹的数据= =
题目连接:http://poj.org/problem?id=3026
这题数据太坑了。。。不看解题报告不知道。。。尼玛,m,n后面不能加getchar(),得加gets(s);尼玛是有多少个空格啊~wa了N遍啊
思路 先求点,然后对每一个点进行一次bfs,然后存距离,之后直接最小生成树。一开始我是用两个for循环去的值,直接超时。。。
代码:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include <iostream> 2 #include <stdio.h> 3 #include <string.h> 4 5 using namespace std; 6 struct node 7 { 8 int x,y; 9 }p[5005]; 10 struct queue 11 { 12 int x,y,step; 13 }q[100005]; 14 int m,n,to[4][2]={{1,0},{-1,0},{0,1},{0,-1}}; 15 int map[505][505]; 16 char str[505][505]; 17 int hash[505][505] = {0}; 18 int is_in(struct queue temp) 19 { 20 if(temp.x >= 0 && temp.x < n && temp.y >= 0 && temp.y < m ) 21 { 22 return 1; 23 } 24 return 0; 25 } 26 27 void bfs(int s) 28 { 29 int vis[505][505] = {0}; 30 int f,r,i; 31 f = r = 0; 32 q[f].x = p[s].x; 33 q[f].y = p[s].y; 34 q[f].step = 0; 35 vis[p[s].x][p[s].y] = 1; 36 r++; 37 while( f<r ) 38 { 39 struct queue temp; 40 temp = q[f++]; 41 for(i = 0;i < 4;i++) 42 { 43 struct queue now; 44 now.x = temp.x+to[i][0]; 45 now.y = temp.y+to[i][1]; 46 now.step = temp.step+1; 47 if(is_in(now)&&str[now.x][now.y] != '#' &&!vis[now.x][now.y]) 48 { 49 q[r++] = now; 50 vis[now.x][now.y] = 1; 51 if(str[now.x][now.y] != ' ') 52 map[s][hash[now.x][now.y]] = map[hash[now.x][now.y]][s] = now.step; 53 } 54 } 55 } 56 } 57 int prim(int sn) 58 { 59 int i,j,primer,ans,min; 60 int vis[505] = {0}; 61 int d[505]; 62 ans = 0; 63 for(i = 0;i < sn;i++) 64 d[i] = map[0][i]; 65 vis[0] = 1; 66 67 for(i = 1;i < sn;i++) 68 { 69 min = 9999999; 70 for(j = 1;j < sn;j++) 71 { 72 if(min > d[j]&& !vis[j]) 73 min = d[j],primer = j; 74 } 75 ans += min; 76 vis[primer] = 1; 77 for(j = 1;j < sn;j++) 78 if(d[j] > map[primer][j] && !vis[j]) 79 d[j] = map[primer][j]; 80 } 81 return ans; 82 } 83 int main() 84 { 85 int t,i,j,count; 86 scanf("%d",&t); 87 while(t--) 88 { 89 memset(hash,0,sizeof(hash)); 90 scanf("%d %d",&m,&n); 91 char s[500]; 92 gets(s); 93 for(i = 0;i < n;i++) 94 { 95 gets(str[i]); 96 } 97 count = 0; 98 for(i = 0;i < n;i++) 99 { 100 for(j = 0;j < m;j++) 101 if(str[i][j] != '#' && str[i][j] != ' ' ) 102 { 103 p[count].x = i; 104 p[count].y = j; 105 hash[i][j] = count; 106 count++; 107 } 108 } 109 110 for(i = 0;i < count;i++) 111 { 112 bfs(i); 113 } 114 printf("%d\n",prim(count)); 115 } 116 return 0; 117 }