【HDU1879】继续畅通工程（MST基础题）

真心大水题。。。不多说。

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cctype>
#include <cmath>
#include <algorithm>
#include <numeric>

#define typec int
using namespace std;

const typec inf = 0xffff;
const int V = 105;
int vis[V];
typec lowc[V], Map[V][V];

typec prim (typec cost[][V], int n) {
    int i, j, p;
    typec minc, res = 0;
    memset(vis, 0, sizeof(vis));
    vis[0] = 1;
    for (i = 1; i < n; ++ i) lowc[i] = cost[0][i];
    for (i = 1; i < n; ++ i) {
        minc = inf;
        p = -1;
        for (j = 0 ; j < n; ++ j) {
            if (0 == vis[j] && minc > lowc[j]) {
                minc = lowc[j];
                p = j;
            }
        }
        if (inf == minc) return -1;
        res += minc;
        vis[p] = 1;
        for (j = 0 ; j < n; ++ j) {
            if (0 == vis[j] && lowc[j] > cost[p][j]) {
                lowc[j] = cost[p][j];
            }
        }
    }
    return res;
}

int main () {
    int n;
    while (~scanf("%d", &n)) {
        if (!n) break;
        for (int i = 0 ; i < V; ++i) {
            for (int j = 0; j < V; ++ j) {
                if (i == j) Map[i][j] = 0;
                else Map[i][j] = inf;
            }
        }

        for (int i = 0 ; i < n * (n - 1) / 2; ++i) {
            int x, y, w, ok;
            scanf("%d%d%d%d", &x, &y, &w, &ok);
            if (!ok) {
                Map[x - 1][y - 1] = Map[y - 1][x - 1] = min(Map[x][y], w);
            } else {
                Map[x - 1][y - 1] = Map[y - 1][x - 1] = 0;
            }
        }

        cout << prim(Map, n) << endl;
    }
    return 0;
}