poj 2502 dijkstra(关键是建图)

点击打开链接//dijkstra 关键是建图#include <iostream>#include<cstdio>#include<cmath>#include<queue>#include<algorithm>#include<cstring>using namespace std;typedef pair<double,int>PII;const int maxn=200+10;const double INF=1e10;struct point{double x,y;};double G[maxn][maxn];       //储存时间point pos[maxn];            //储存坐标double d[maxn];                 //储存到各点的最短时间bool done[maxn];int ans;void dijkstra(int start){    memset(done,false,sizeof(done));    for(int i=0;i<ans;i++)        d[i]=(i==start?0:INF);    priority_queue<PII,vector<PII>,greater<PII> >pq;    pq.push(PII(d[start],start));    while(!pq.empty())    {        PII k=pq.top();        pq.pop();        int v1=k.second;        if(done[v1]) continue;        done[v1]=true;        for(int i=0;i<ans;i++)        {            if(d[i]>d[v1]+G[v1][i])            {                d[i]=d[v1]+G[v1][i];                pq.push(PII(d[i],i));            }        }    }}int main(){    ans=2;    int flag=0;    cin>>pos[0].x>>pos[0].y>>pos[1].x>>pos[1].y;    memset(G,0,sizeof(G));    while(cin>>pos[ans].x>>pos[ans].y)    {        if(pos[ans].x==-1&&pos[ans].y==-1)        {            flag=0;            continue;        }        if(flag)        {            double temp=hypot(pos[ans].x-pos[ans-1].x,pos[ans].y-pos[ans-1].y)/40000.0;            G[ans][ans-1]=G[ans-1][ans]=temp;        }        flag=1;        ans++;    }    for(int i=0;i!=ans;i++)    for(int j=0;j!=ans;j++)    {        if(i!=j&&G[i][j]==0.0)        G[i][j]=G[j][i]=hypot(pos[i].x-pos[j].x,pos[i].y-pos[j].y)/10000.0;    }    dijkstra(0);    cout<<int(60.0*d[1]+0.5)<<endl;    return 0;}