POJ 3026 Borg Maze

Minimum spanning Tree +bfs

Test instructions is to find the smallest spanning tree in the maze that connects all points. Other miscellaneous items are entirely disregarded. It took me a long time to understand test instructions.

I used the Kruskal. Each point is labeled at the time of input. Then BFS every point. Find out all the recent edges, and then the template Kruskal.

Because it is a labyrinth, it is only possible to use BFS to search the shortest path to every point it communicates with.

Just the data a bit of a pit, the proposed array is larger, I submit the time re once. Definitely more than 100 points.

Then after you have entered the length and width. Unexpectedly still have inexplicable space, so can not getchar, directly get a bar, this let me wa once.

And then it came down to AC.

。

#include <cstdio> #include <cstring> #include <string> #include <queue> #include <algorithm > #include <queue> #include <map> #include <stack> #include <iostream> #include <list># include<set> #include <cmath> #define INF 0x7fffffff#define eps 1e-6using namespace std;int n,m,xl,yl;int cot ; int xx[]= { -1,1,0,0};int yy[]= {0,0,-1,1};struct lx{int u,v,len;} l[50*1001];int fa[1001];bool Vis[151][151];char g[1 51][151];int site[151][151];struct node{int x,y,lv;} point[1001];bool cmp (lx A,lx b) {return a.len<b.len;} int father (int x) {if (x!=fa[x]) return Fa[x]=father (Fa[x]);}    void BFS (node S) {memset (vis,0,sizeof (VIS));    queue<node>q;    Q.push (S);    Vis[s.x][s.y]=1;    int U=SITE[S.X][S.Y];    int num=1;        while (!q.empty ()) {node now,tmp;        Tmp=q.front (); Q.pop ();        int V=SITE[TMP.X][TMP.Y];            if (v>=1&&u!=v) {l[cot].u=u;            L[cot].v=v; l[cot++].len=tmp.lv;        num++;        } if (num==n) break;            for (int k=0;k<4;k++) {int x=tmp.x+xx[k];            int y=tmp.y+yy[k]; if (y>=yl| | y<0| | x>=xl| | x<0| | g[x][y]== ' # ' | |            Vis[x][y]) continue;            Vis[x][y]=1;            now.lv=tmp.lv+1;            Now.x=x,now.y=y;        Q.push (now);    }}}int Main () {int t;    scanf ("%d", &t);        while (t--) {scanf ("%d%d", &xl,&yl);        Char str[51];        memset (site,0,sizeof (site));        N=1;        Gets (str);            for (int i=0; i<yl; i++) {gets (str);                for (int j=0; j<xl; J + +) {G[i][j]=str[j]; if (str[j]== ' A ' | |                    str[j]== ' S ') {site[i][j]=n;                    Point[n].x=i,point[n].y=j;                point[n++].lv=0;        }}} cot=0;        n--;  for (int i=1; i<=n; i++)          BFS (Point[i]);        for (int i=1; i<=n; i++) fa[i]=i;        Sort (l,l+cot,cmp);        int ans=0;            for (int i=0;i<cot;i++) {int fu=father (L[I].U);            int Fv=father (L[I].V);            if (FU==FV) continue;            Fa[fv]=fu;        Ans+=l[i].len;    } printf ("%d\n", ans); }}

POJ 3026 Borg Maze