【POJ 3026】Borg Maze

標籤：最小產生樹   廣搜   

【POJ 3026】Borg Maze

一個考察隊搜尋alien 這個考察隊可以無限分割 問搜尋到所有alien所需要的總步數 即求一個無向圖 包含所有的點並且總權值最小(最小產生樹

BFS+最小產生樹

Prim/Kruskal…懶死了 就這麼貼吧……湊活看(￣┰￣*)

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <queue>#include <algorithm>#define INF 0x3f3f3f3fusing namespace std;typedef struct Point{    int x,y;}Point;typedef struct Edge{    int u,v,w;    bool operator < (const struct Edge a)const    {        return w < a.w;    }}Edge;Edge eg[10100];bool vs[101][101];Point p[101];char mp[51][52];int id[51][51];int dis[101][101];bool vis[51][51];//int dss[101];//bool vs[101];int dirx[] = { 0, 0, 1,-1};int diry[] = { 1,-1, 0, 0};int ds[51][51];int tp,x,y,top;int pre[101];void Bfs(int xx,int yy){    memset(vis,0,sizeof(vis));    queue <pair<int,int> > q;    q.push(pair<int,int> (xx,yy));    vis[xx][yy] = 1;    ds[xx][yy] = 0;    int i,aa,bb,a,b;    while(!q.empty())    {        pair <int,int> pt = q.front();        q.pop();        a = pt.first;        b = pt.second;        for(i = 0; i < 4; ++i)        {            aa = a+dirx[i];            bb = b+diry[i];            if(aa > x || bb > y || aa < 1 || bb < 1 || mp[aa][bb] == ‘#‘ || vis[aa][bb]) continue;            ds[aa][bb] = ds[a][b]+1;            vis[aa][bb] = 1;            q.push(pair<int,int> (aa,bb));//            if(mp[aa][bb] != ‘ ‘) dis[id[xx][yy]][id[aa][bb]] = dis[id[aa][bb]][id[xx][yy]] = ds[aa][bb];            if(mp[aa][bb] != ‘ ‘ && !vs[id[xx][yy]][id[aa][bb]])            {                vs[id[xx][yy]][id[aa][bb]] = vs[id[aa][bb]][id[xx][yy]] = 1;                eg[top].u = id[xx][yy];                eg[top].v = id[aa][bb];                eg[top++].w = ds[aa][bb];            }        }    }}void Init(int n){    int i;    for(i = 0; i < n; ++i)        pre[i] = i;}int Find(int x){    if(x != pre[x]) pre[x] = Find(pre[x]);    return pre[x];}//int Prim()//{//    memset(vs,0,sizeof(vs));//    memset(dss,INF,sizeof(dss));//    dss[0] = 0;//    int i,j,p,w,sum = 0;//    for(i = 0; i < tp; ++i)//    {//        w = INF;//        for(j = 0; j < tp; ++j)//        {//            if(!vs[j] && w > dss[j])//            {//                w = dss[j];//                p = j;//            }//        }//        sum += w;//        vs[p] = 1;//        for(j = 0; j < tp; ++j)//        {//            if(!vs[j] && dss[j] > dis[p][j])//                dss[j] = dis[p][j];//        }//    }//    return sum;//}int main(){    int n,i,j;    int cnt,sum,k,r;    scanf("%d",&n);    while(n--)    {        memset(vs,0,sizeof(vs));        tp = top = 0;        scanf("%d %d",&y,&x);        gets(mp[0]);        for(i = 1; i <= x; ++i)        {            gets(mp[i]+1);            for(j = 1; mp[i][j]; ++j)            {                if(mp[i][j] != ‘#‘ && mp[i][j] != ‘ ‘)                {                    id[i][j] = tp;                    p[tp].x = i;                    p[tp++].y = j;                }            }        }        Init(tp);        for(i = 0; i < tp; ++i)        {            Bfs(p[i].x,p[i].y);        }//        printf("%d\n",Prim());        sort(eg,eg+top);        sum = cnt = 0;        for(i = 0; i < top; ++i)        {            k = Find(eg[i].u);            r = Find(eg[i].v);            if(k != r)            {                pre[k] = r;                sum += eg[i].w;                cnt++;            }            if(cnt == tp) break;        }        printf("%d\n",sum);    }    return 0;}

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【POJ 3026】Borg Maze