HDU : 1301 (Jungle Roads)



// http://acm.hdu.edu.cn/showproblem.php?pid=1301
// Runtime: 0ms
// Tag: MST, Kruskal 

// @BEGIN_OF_SOURCE_CODE

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <cctype>
#include <stack>
#include <queue>
#include <list>
#include <vector>
#include <map>
#include <sstream>
#include <cmath>
#include <bitset>
#include <utility>
#include <set>
#include <numeric>

#define INF_MAX 2147483647
#define INF_MIN -2147483647
#define pi acos(-1.0)
#define N 1000
#define LL long long

#define For(i, a, b) for( int i = (a); i < (b); i++ )
#define Fors(i, sz) for( size_t i = 0; i < sz.size (); i++ )
#define Fore(it, x) for(typeof (x.begin()) it = x.begin(); it != x.end (); it++)
#define Set(a, s) memset(a, s, sizeof (a))
#define Read(r) freopen(r, "r", stdin)
#define Write(w) freopen(w, "w", stdout)

using namespace std;

int parent [30];

struct village {
    int s;
    int e;
    int d;
} a [30];

bool cmp (village p, village q)
{
    if ( p.d < q.d ) return true;
    return false;
}

void reset ()
{
    for ( int i = 0; i < 30; i++ ) parent [i] = i;
}

int parentOf (int n)
{
    if ( n == parent [n] ) return n;
    return parent [n] = parentOf (parent [n]);
}

int main ()
{
    // Read ("in.in");
    int vertex;

    while ( scanf ("%d", &vertex ) && vertex ) {

        reset ();
        int ind = 0;

        for ( int i = 1; i < vertex; i++ ) {
            char start [3]; scanf ("%s", start);
            int k; scanf ("%d", &k);
            for ( int j = 0; j < k; j++ ) {
                char end [3]; scanf ("%s", end);
                scanf ("%d", &a [ind].d);
                a [ind].s = start [0] - 'A';
                a [ind].e = end [0] - 'A';
                ind++;
            }
        }

        sort (a, a + ind, cmp);

        int totalCost = 0;
        int selectedEdges = vertex - 1;

        for ( int i = 0; i < ind && selectedEdges; i++ ) {
            int p = parentOf (a [i].s);
            int q = parentOf (a [i].e);

            if ( p != q ) {
                parent [p] = q;
                selectedEdges--;
                totalCost += a [i].d;
            }
        }

        printf ("%d\n", totalCost);
    }

	return 0;
}

// @END_OF_SOURCE_CODE
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