专题四 · 1004

Posted 2022-11-26 suamfadmp

代码及解释

#include <iostream>
#include <algorithm>

// 刚刚考完计算机组成，赶快做一道题��
// 连续好几道 Kruskal，代码几乎都不用改（感谢老师��）
//

using std::cin;
using std::cout;
using std::endl;

const int N = 200;

int set[N];

int find_f(int x) 
  if (x != set[x])
    set[x] = find_f(set[x]);
  return set[x];


struct edge 
  int x, y, v;
 e[N*(N - 1) / 2];

inline int cmp(edge e1, edge e2) 
  return e1.v<e2.v;


int main() 
  int n;
  while (cin >> n && n) 
    for (int i = 0; i <= n; ++i)
      set[i] = i;

    n = n * (n - 1) / 2;

    for (int i = 0; i<n; i++)
      cin >> e[i].x >> e[i].y >> e[i].v;

    std::sort(e, e + n, cmp);
    int ans = 0;

    for (int i = 0; i < n; ++i) 
      int x = find_f(e[i].x);
      int y = find_f(e[i].y);
      if (x != y) 
        ans += e[i].v;
        set[x] = y;
      
    
    cout << ans << endl;
  
  return 0;