这么简单的题怎么能没题解呢

#include <cstdio>
#include <algorithm>
#include <iostream>
using namespace std;
int n, m, f[40001], vis[40001], x, y, z;
struct data
{
    int a, b, c;
} e[100001];
int comp(data a, data b)
{
    return a.c > b.c;
}
int find(int x)
{
    return f[x] == x ? x : f[x] = find(f[x]);
}
int main()
{
    cin >> n >> m;
    for (int i = 1; i <= m; i++)
        cin >> e[i].a >> e[i].b >> e[i].c;
    for (int i = 1; i <= n; i++)
        f[i] = i;
    sort(e + 1, e + m + 1, comp);
    for (int i = 1; i <= m; i++)
    {
        x = find(e[i].a);
        y = find(e[i].b);
        if (x == y)
        {
            cout << e[i].c;
            return 0;
        }
        else
        {
            if (vis[e[i].a])
            {
                z = find(vis[e[i].a]);
                f[y] = z;
            }
            else
                vis[e[i].a] = e[i].b;
 
            if (vis[e[i].b])
            {
                z = find(vis[e[i].b]);
                f[x] = z;
            }
            else
                vis[e[i].b] = e[i].a;
        }
    }
    cout << 0;
    return 0;
}