【CodingTrip - 携程编程大赛第三场】1003 携程全球数据中心建设

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来源：HDU 携程编程大赛第一场

简单Prim，不过用一种很高端洋气的经纬度表示方法来表示两点之间的距离。gis学的东东。把距离合到map里边，最后就是套用prim模板的问题。

#include <iostream>#include <cmath>#include <cstring>using namespace std;double map[105][105];const double pi=3.14159265358979323846;const double INF=0x3f3f3f3f;int pointnum;int n;double prim(){    double low[105];    int flag[105];    memset(flag,0,sizeof(flag));    for(int i=1; i<=pointnum; i++)    {        low[i]=map[1][i];    }    double count=0;    flag[1]=1;    for(int i=1; i<pointnum; i++)    {        double min=INF+1;        int k;        for(int j=1; j<=pointnum; j++)        {            if(flag[j]==0 && min>low[j])            {                min=low[j];                k=j;            }        }        flag[k]=1;        count+=low[k];        for(int j=1; j<=pointnum; j++)        {            if(flag[j]==0&&low[j]>map[j][k])            {                low[j]=map[j][k];            }        }    }    return count;}void init(){    for(int i=1;i<105;i++)    {        for(int j=1;j<105;j++)            map[i][j]=INF;    }}class latipoint{    public:        double lat;        double lng;};double EARTH_RADIUS;double rad(double d){     return d * pi / 180.0;}double GetDistance(double lat1, double lng1, double lat2, double lng2){    double radLat1 = rad(lat1);    double radLat2 = rad(lat2);    double a = radLat1 - radLat2;    double b = rad(lng1) - rad(lng2);    double s = 2 * asin(sqrt(pow(sin(a/2),2) + cos(radLat1) * cos(radLat2) *pow(sin(b/2),2)));    s = s * EARTH_RADIUS/2.0;    return s;}int main(){    int testcase;    cin>>testcase;    while(testcase--)    {        init();        latipoint point[105];        double LineLength;        cin>>EARTH_RADIUS>>LineLength;        cin>>pointnum;        for(int i=1;i<=pointnum;i++)        {            cin>>point[i].lat>>point[i].lng;        }        n=pointnum*pointnum;        for(int i=1;i<=pointnum;i++)        {            for(int j=1;j<=pointnum;j++)            {                if(i!=j)                {                    map[i][j]=GetDistance(point[i].lat,point[i].lng,point[j].lat,point[j].lng);                    //cout<<"map"<<i<<"to:"<<j<<"is:  "<<map[i][j]<<endl;                }            }        }        double ret=prim();        //cout<<"haha:"<<ret<<"hehe:"<<LineLength<<endl;        if(ret>LineLength)            cout<<"N"<<endl;        else            cout<<"Y"<<endl;    }    return 0;}

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