HDU-6187(Destory Wall)

国王要到达每一个点要求图不能有环, 所以按照要求, 去掉墙的数量少, 去掉墙的花费小, 可转化为最大生成树求解

#include <algorithm>
#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;

const int MAXN = 200010;

struct _Edge {
  int u, v, cost;
  bool operator<(const _Edge rhs) const { return cost > rhs.cost; }
};

_Edge E[MAXN];
int f[MAXN];

int Find(int x) { return f[x] == -1 ? x : f[x] = Find(f[x]); }
bool Union(int a, int b) {
  int x = Find(a);
  int y = Find(b);
  f[y] = x;
  return x != y;
}
int main() {
  int n, m, total, num;
  while (scanf("%d%d", &n, &m) != EOF) {
    total = 0;
    num = 0;
    for (int i = 0; i < MAXN; ++i)
      f[i] = -1;
    for (int i = 1; i <= n; ++i) {
      int x, y;
      cin >> x >> y;
    }
    for (int i = 0; i < m; ++i) {
      cin >> E[i].u >> E[i].v >> E[i].cost;
      total += E[i].cost;
    }
    sort(E, E + m);
    for (int i = 0; i < m; ++i) {
      if (Find(E[i].u) != Find(E[i].v)) {
        Union(E[i].u, E[i].v);
        num++;
        total -= E[i].cost;
      }
    }
    printf("%d %d\n", m - num, total);
  }
  return 0;
}