【Kruskal】P3366 【模板】最小生成树

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

struct Node
{
    int u, v, w;
}node[200005];

int s[5005];
int n, m;
int cnt;
int sum;

bool cmp(Node a, Node b)
{
    return a.w < b.w;
}

int find(int a)
{
    while (a != s[a])
    {
        s[a] = s[s[a]];
        a = s[a];
    }
    return a;
}

void kruskal()
{
    sort(node, node + m, cmp);
    for (int i = 0; i < m; i++)
    {
        int t1, t2;
        t1 = find(node[i].u);
        t2 = find(node[i].v);
        if (t1 == t2)
        {
            continue;
        }//通过并查集检测两节点是否连通
        sum += node[i].w;
        s[t2] = t1;
        cnt++;
        if (cnt == n - 1) break;
    }
}
int main()
{
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        s[i] = i;
    }
    for (int i = 0; i < m; i++)
    {
        cin >> node[i].u >> node[i].v >> node[i].w;
    }
    kruskal();
    cout << sum;
}