Hdu 1162 Eddy & amp; #39; s picture (Basic minimal spanning tree)

Question:

Connection: Click the open link.

Question:

N vertices are connected to each other (directly and indirectly) to obtain the shortest distance.

Ideas:

Prim () Minimum Spanning Tree. Store the distance of a vertex in map.

Code:

#include
 
  #include
  
   #include
   
    #include
    
     using namespace std;#define MAXN 110#define MAX 100000000struct node{    double x,y;}p[MAXN];double map[MAXN][MAXN];double low[MAXN];int vis[MAXN];int n;void prim(){    int pos;    double minn;    double result = 0;    memset(vis,0,sizeof(vis));    pos = 1;    vis[pos] = 1;    for(int i=1; i<=n; i++)    {        if(i != pos)            low[i] = map[pos][i];    }    for(int i=1; i
     
       low[j])            {                minn = low[j];                pos = j;            }        }        result += minn;        vis[pos] = 1;        for(int j=1; j<=n; j++)        {            if(!vis[j] && map[pos][j] < low[j])                low[j] = map[pos][j];        }    }    printf("%.2lf\n",result);}int main(){    //freopen("input.txt","r",stdin);    while(scanf("%d",&n) != EOF)    {        for(int i=1; i<=n; i++)            scanf("%lf%lf",&p[i].x,&p[i].y);        for(int i=1; i<=n; i++)        {            for(int j=1; j<=n; j++)                map[i][j] = sqrt((p[i].x-p[j].x)*(p[i].x-p[j].x) + (p[i].y-p[j].y)*(p[i].y-p[j].y));        }        prim();    }    return 0;}
     
    
   
  
 

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Combat, never stop ~~~~~~~~~~~~~~~~~~~~~