P3366 【模板】最小生成树 （贪心+并查集，kruskal）

#define _CRT_SECURE_NO_DepRECATE
#define _CRT_SECURE_NO_WARNINGS
#include <cstdio>
#include <iostream>
#include <cmath>
#include <iomanip>
#include <string>
#include <algorithm>
#include <bitset>
#include <cstdlib>
#include <cctype>
#include <iterator>
#include <vector>
#include <cstring>
#include <cassert>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <stdio.h>
#define ll long long
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define ld long double
#define rep(i, a, b) for(int i = a; i < (b); ++i)
const ld pi = acos(-1.0L), eps = 1e-8;
ll qx[4] = { 0,0,1,-1 }, qy[4] = { 1,-1,0,0 }, qxx[2] = { 1,-1 }, qyy[2] = { 1,-1 };
using namespace std;
int n, m, a, b, c, d, e, ans = 0, cnt = 0;
struct node
{
    int parent, shu;
}shu[10010];
struct nodee
{
    int x, y, z;//x,y为点 z为权值
}tu[200010];
bool cmp(nodee x, nodee y)//排序权值
{
    return x.z < y.z;
}
int find(int x)
{
    while (shu[x].parent != x)
    {
        x = shu[x].parent = shu[shu[x].parent].parent;
    }
    return x;
}
inline void kruskal()
{
    sort(tu, tu + m, cmp);
    rep(i, 0, m)
    {
        d = find(tu[i].x);
        e = find(tu[i].y);
        if (d == e)//当两点已连通则换下一条边
        {
            continue;
        }
        ans += tu[i].z;
        shu[d].parent = e;//合并
        if (++cnt == n - 1)//已经全部合并的时候就结束循环
        {
            break;
        }
    }
}
int main() 
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        shu[i].parent = i;
    }
    rep(i, 0, m)
    {
        cin >> tu[i].x >> tu[i].y >> tu[i].z;
    }
    kruskal();
    if (ans == 0)
    {
        cout << "orz" << endl;
        return 0;
    }
    cout << ans << endl;
    return 0;
}