POJ 3723 Conscription 最小生成树

#include 
#include 
using namespace std;
struct Edge
{
    int from, to, cost;
    Edge(int from = 0, int to = 0, int cost = 0) : from(from), to(to), cost(cost) {}
};
int par[20007], ranks[20007], N, M, R, inf = 10000, mincost[20007];
Edge edges[50007];
bool compareEdge(const Edge &edge1, const Edge &edge2)
{
    return edge1.cost < edge2.cost;
}
void init()
{
    for (int i = 0; i <= 20000; i++)
    {
        par[i] = i;
        ranks[i] = 1;
    }
}
int find(int x)
{
    if (par[x] == x)
    {
        return x;
    }
    else
    {
        return par[x] = find(par[x]);
    }
}
void unite(int x, int y)
{
    x = find(x);
    y = find(y);
    if (x == y)
    {
        return;
    }
    if (ranks[x] < ranks[y])
    {
        par[x] = y;
    }
    else
    {
        par[y] = x;
        if (ranks[x] == ranks[y])
        {
            ranks[x]++;
        }
    }
}
bool same(int x, int y)
{
    return find(x) == find(y);
}
void input()
{
    scanf("%d%d%d", &N, &M, &R);
    int from, to, cost;
    for (int i = 1; i <= R; i++)
    {
        scanf("%d%d%d", &from, &to, &cost);
        edges[i] = Edge(from, to + N, -cost);
    }
    N = N + M;
}
int kruskal()
{
    sort(edges + 1, edges + 1 + R, compareEdge);
    int ans = 0;
    for (int i = 1; i <= R; i++)
    {
        if (same(edges[i].from, edges[i].to))
        {
            continue;
        }
        unite(edges[i].from, edges[i].to);
        ans += edges[i].cost;
    }
    return ans;
}
int findAns()
{
    int ans = N * 10000;
    ans += kruskal();
    return ans;
}
int main()
{
    int t;
    scanf("%d", &t);
    while (t--)
    {
        input();
        init();
        printf("%d\n", findAns());
    }
    return 0;
}