poj1258

/*
    Made by Karen
    20:30 at Mar.5,2012
    Kruskal
*/
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
#define max_ve 120
#define max_ed 14400
struct node
{
    int par,ans;
}Vertex[max_ve];
struct Edge
{
    int u,v,weight;
}edge[max_ed];
int cmp(const void *a,const void *b)
{
    return (*(Edge*)a).weight-(*(Edge*)b).weight;
}
int find(int j)
{
    if(Vertex[j].par!=j)
        Vertex[j].par=find(Vertex[j].par);
    return Vertex[j].par;
}
bool union_set(int s,int t)
{
    int os=find(s),ot=find(t);
    if(os==ot)
        return false;
    if(Vertex[os].ans>Vertex[ot].ans)
        Vertex[ot].par=os;
    else
        Vertex[os].par=ot;
    if(Vertex[os].ans==Vertex[ot].ans)
        Vertex[ot].ans++;
    return true;
}
int main()
{
    int n,i,j,sum,ct,k,c;
    while(scanf("%d",&n)!=EOF)
    {
        for(i=1;i<=n;i++)
        {
            Vertex[i].par=i;
            Vertex[i].ans=0;
        }
        k=0;
        for(i=1;i<=n;i++)
            for(j=1;j<=n;j++)
            {
                scanf("%d",&c);
                if(i<j)
                {
                    edge[k].u=i;
                    edge[k].v=j;
                    edge[k].weight=c;
                    k++;
                }
            }
        qsort(edge,k,sizeof(edge[1]),cmp);
        sum=0;ct=0;
        for(i=0;i<k&&ct<n-1;i++)
        {
            if(union_set(edge[i].u,edge[i].v))
            {
                ct++;
                sum+=edge[i].weight;
            }
        }
        printf("%d\n",sum);
    }
    return 0;
}