hdu 1301(最小生成树kruskal)

/*

  Name: 最小生成树(kruskal) 

  Author: Try_86

  Date: 10/04/12 19:51

*/



#include <cstdio>

#include <cstdlib>

#include <iostream>



using namespace std;



const int M = 700;



int p[27], sum;

struct edge {

    int a;

    int b;

    int w;

}e[M];



int cmp(const void *a, const void *b) {

    return (*(edge *)a).w - (*(edge *)b).w;

}



void init(int vs) {

    for (int i=1; i<=vs; ++i) p[i] = i;

    return ;

}



int find(int v) {

    if (p[v] != v) p[v] = find(p[v]);

    return p[v];

}



int join(edge e) {

    int x, y;

    x = find(e.a);

    y = find(e.b);

    if (x != y) {

        ++sum;

        p[x] = y;

        return e.w;

    }

    return 0;

}



int kruskal(int es, int vs) {

    int ans = 0;

    init(vs);

    qsort(e, es, sizeof(edge), cmp);

    for (int i=0; i<es; ++i) {

        ans += join(e[i]);

        if (sum == vs) return ans;

    }

}



int main() {

    int n;

    while (cin>>n) {

        if (n == 0) break;

        char c;

        int k, w, es;

        es = 0;

        for (int i=1; i<n; ++i) {

            cin>>c>>k;

            for (int j=0; j<k; ++j) {

                cin>>c>>w;

                e[es].w = w;

                e[es].a = i;

                e[es].b = c - 'A' + 1;

                ++es;

            }

        }

        sum = 1;

        int ans = kruskal(es, n);

        printf ("%d\n", ans);

    }

    return 0;

}