【HDU1233】还是畅通工程（MST基础题）

无坑，裸题。直接敲就恩那个AC。

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

#define typec int
using namespace std;

const int V = 105;
const int inf = 0xffff;
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 (int i = 1; i < n; ++ i) lowc[i] = cost[0][i];
    for (int 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) && n) {
        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, c; scanf("%d%d%d", &x, &y, &c);
            if (x == y) continue;
            Map[x - 1][y - 1] = Map[y - 1][x - 1] = min(Map[x - 1][y - 1], c);
        }
        cout << prim(Map, n) << endl;
    }
    return 0;
}