就是用并查集做的，也没看出来和题解里的ac代码有什么本质区别

#include <bits/stdc++.h>
using namespace std;

inline int read() {
	int p = 0, f = 1;
	char c = getchar();
	while (c < '0' || c > '9') {
		if (c == '-')
			f = -1;
		c = getchar();
	}
	while (c >= '0' && c <= '9') {
		p = p * 10 + c - '0';
		c = getchar();
	}
	return f * p;
}

struct A {
	int b, e, w;

} p[100010];
int q[10010];
int r[10010];

bool cmp(A a, A b) {
	if (a.w > b.w)
		return true;
	else
		return false;
}

int find(int x) {
	if (q[x] == x)
		return x;
	else {
		q[x] = find(q[x]);
		return q[x];
	}
}

int main () {
	int n, m;
	cin >> n >> m;
	memset(r, 0, sizeof(r));
	int a, b;
	for (int i = 1; i <= m; i++) {
		p[i].b = read();
		p[i].e = read();
		p[i].w = read();
	}
	sort(p + 1, p + m + 1, cmp);
	for (int i = 1; i < n; i++) {
		q[i] = i;
	}
	for (int i = 1; i <= m; i++) {
		int t1 = find(p[i].b);
		int t2 = find(p[i].e);
		if (t1 == t2) {
			cout << p[i].w;
			return 0;
		}
		if (!r[p[i].b])
			r[p[i].b] = p[i].e;
		else
			q[find(r[p[i].b])] = p[i].e;
		if (!r[p[i].e])
			r[p[i].e] = p[i].b;
		else
			q[find(r[p[i].e])] = p[i].b;
	}
	cout << "0";
}