Hdu 1875 畅通工程再续 程序参考

#include<iostream>#include<cmath>#include<vector>using namespace std;const int Max=1001;vector <vector <double> > mat;vector <double> dist;vector <bool>  visited;int n;int minVertex(){    int next=-1;for (int i=0;i<n;i++){if (visited[i]==false && (next==-1 || dist[i]<dist[next])){next = i;}}    return next;}double Prim(){dist=mat[0];fill(visited.begin(),visited.end(),false);    visited[0]=true; double cost=0;int i;bool flag=true;for(i=1;i<n;i++){        int next=minVertex();visited[next]=true;if (dist[next]==Max) //不连通{flag=false;break;}        cost+=dist[next];        for (int j=0;j<n;j++){if (visited[j]==false && mat[next][j]<dist[j]) {dist[j]=mat[next][j];}}    }if (flag==false)return -1;elsereturn cost;}struct Position{int x,y;};vector <Position> islands;double dist2Pos(Position a,Position b){return sqrt((double)((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y)));}void run(){scanf("%d",&n);islands.resize(n);int i;for(i=0;i<n;i++) scanf("%d %d",&islands[i].x,&islands[i].y);mat.resize(n);visited.resize(n); for(i=0; i<n; i++)    {mat[i].resize(n);fill(mat[i].begin(),mat[i].end(),Max);mat[i][i]=0;}for(i=0; i<n; i++){        for(int j=0;j<n;j++)        {double d=dist2Pos(islands[i],islands[j]);if (d>=10 && d<=1000){mat[i][j]=d;mat[j][i]=d;}        }}    double cost=Prim();if (cost!=-1)printf("%.1lf/n",cost*100);elseprintf("oh!/n");}int main(){int total;scanf("%d",&total);for(int now=1; now<=total; now++) run();return 0;}