Borg Maze(BFS+MST)
阿新 • • 發佈:2018-11-19
Borg Maze
http://poj.org/problem?id=3026
Time Limit: 1000MS | Memory Limit: 65536K | |
Total Submissions: 18230 | Accepted: 5870 |
Description
The Borg is an immensely powerful race of enhanced humanoids from the delta quadrant of the galaxy. The Borg collective is the term used to describe the group consciousness of the Borg civilization. Each Borg individual is linked to the collective by a sophisticated subspace network that insures each member is given constant supervision and guidance.Your task is to help the Borg (yes, really) by developing a program which helps the Borg to estimate the minimal cost of scanning a maze for the assimilation of aliens hiding in the maze, by moving in north, west, east, and south steps. The tricky thing is that the beginning of the search is conducted by a large group of over 100 individuals. Whenever an alien is assimilated, or at the beginning of the search, the group may split in two or more groups (but their consciousness is still collective.). The cost of searching a maze is definied as the total distance covered by all the groups involved in the search together. That is, if the original group walks five steps, then splits into two groups each walking three steps, the total distance is 11=5+3+3.
Input
Output
Sample Input
2 6 5 ##### #A#A## # # A# #S ## ##### 7 7 ##### #AAA### # A# # S ### # # #AAA### #####
Sample Output
8 11
Source
Svenskt Mästerskap i Programmering/Norgesmesterskapet 2001
很坑,資料n,m後面有很長的空格,要用gets讀掉
1 #include<iostream> 2 #include<algorithm> 3 #include<queue> 4 #include<cstring> 5 #include<cmath> 6 #include<cstdio> 7 using namespace std; 8 9 struct sair{ 10 int x,y,step; 11 }p[100005]; 12 int fa[100005]; 13 int n,m; 14 15 int Find(int x){ 16 int r=x,y; 17 while(x!=fa[x]){ 18 x=fa[x]; 19 } 20 while(r!=x){ 21 y=fa[r]; 22 fa[r]=x; 23 r=y; 24 } 25 return x; 26 } 27 28 int join(int x,int y){ 29 int xx=Find(x); 30 int yy=Find(y); 31 if(xx!=yy){ 32 fa[xx]=yy; 33 return true; 34 } 35 return false; 36 } 37 38 struct DIST{ 39 int x,y,dis; 40 }dis[1000005]; 41 42 bool cmp(DIST a,DIST b){ 43 return a.dis<b.dis; 44 } 45 46 int dir[4][2]={0,1,1,0,0,-1,-1,0}; 47 int co; 48 49 char mp[505][505]; 50 int book[505][505]; 51 52 void BFS(int x,int y){ 53 queue<sair>Q; 54 memset(book,0,sizeof(book)); 55 sair s,e; 56 s.x=x,s.y=y,s.step=0;; 57 Q.push(s); 58 while(!Q.empty()){ 59 s=Q.front(); 60 Q.pop(); 61 for(int i=0;i<4;i++){ 62 e.x=s.x+dir[i][0]; 63 e.y=s.y+dir[i][1]; 64 if(e.x>=0&&e.x<n&&e.y>=0&&e.y<m&&!book[e.x][e.y]&&mp[e.x][e.y]!='#'){ 65 e.step=s.step+1; 66 Q.push(e); 67 book[e.x][e.y]=1; 68 if(mp[e.x][e.y]=='A'||mp[e.x][e.y]=='S'){ 69 dis[co].x=x*m+y+1,dis[co].y=e.x*m+e.y+1,dis[co++].dis=e.step; 70 } 71 } 72 } 73 } 74 } 75 76 int main(){ 77 int T; 78 scanf("%d",&T); 79 while(T--){ 80 co=0; 81 char dd[105]; 82 scanf("%d %d",&m,&n); 83 gets(dd); 84 for(int i=0;i<=m*n;i++) fa[i]=i; 85 for(int i=0;i<n;i++) gets(mp[i]); 86 for(int i=0;i<n;i++){ 87 for(int j=0;j<m;j++){ 88 if(mp[i][j]=='S'||mp[i][j]=='A'){ 89 BFS(i,j); 90 } 91 } 92 } 93 sort(dis,dis+co,cmp); 94 int ans=0; 95 for(int i=0;i<co;i++){ 96 if(join(dis[i].x,dis[i].y)){ 97 ans+=dis[i].dis; 98 } 99 } 100 printf("%d\n",ans); 101 } 102 } 103 /* 104 1 105 50 7 106 ################################################## 107 # AAAAAAA#AAAAAA AAA S # 108 # AAAAAAAAAA AAAAAAAAAAAAAA#####AAAAA### # 109 # A##A#A#A#A###A#A#A#A#A#A#A#A#A#A#A##A#A# # 110 # A ########### 111 # AAAAAAAAAAAA########## # 112 ################################################## 113 */View Code