Is There A Second Way Left? UVA - 10462 （WA）

//WA了。。。。看不出来哪错了，先留个底....以后再看能不能找出来 

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <string>
#include <stdlib.h>
#include <vector>
#include <queue>
#include <cmath>
#include <stack>
#include <map>
#include <set>
using namespace std;

typedef  long long LL;

const int inf = 0x3f3f3f3f;
const LL N = 1000+5;

int n, m, cnt = 1, k;
struct Edge {
    int u, v, w;
} edge[N * N];
int MAX[N][N];  //最大权值
bool vis[N*N]; 
vector<int> G[N];
int pre[N];

void init(int n) 
{
	memset(vis, 0, sizeof(vis));
	memset(MAX, 0, sizeof(MAX));
    for(int i = 0; i <= n; i++)
        pre[i] = i, G[i].clear(), G[i].push_back(i); 
}

int Find(int x) 
{
  return (x == pre[x]) ? x : pre[x] = Find(pre[x]);
}
bool Union(int x, int y) 
{	
	if(x != y){
		pre[x] = y;
		return true;
	}
	
	return false;
}

bool cmp(const Edge &a, const Edge &b)
{ 
	return a.w < b.w;
}

void Kruskal() 
{
    sort(edge+1, edge+1+m, cmp);
    init(n);
    
	k = 0;
    int sum = 0;
    for(int i = 1; i <= m; i++) {
	    int u = Find(edge[i].u), v = Find(edge[i].v), w = edge[i].w;
    
	    if(Union(u, v)) {
            sum += w, vis[i] = true;
            for(int j = 0; j < G[u].size(); ++j)
                for(int k = 0; k < G[v].size(); ++k)
                    MAX[G[u][j]][G[v][k]] = MAX[G[v][k]][G[u][j]] = w;
           
            for(int j = 0; j < G[u].size(); ++j)
                G[v].push_back(G[u][j]);  //u为v的 子树 
        }
        k++;
        if(k == n-1) break;
    }
    if(k != n-1){
    	cout << "No way" << endl;
    	return;
	}
    int Ssum = inf;
    for(int i = 1; i <= m; ++i)
        if(!vis[i])
            Ssum = min(Ssum, sum+edge[i].w-MAX[edge[i].u][edge[i].v]);
   if(Ssum == inf) cout << "No second way" << endl;
   else cout << Ssum << endl;

}

int main() 
{
    int T;
    cin >> T;
    while(T--){
        cin >> n >> m;
        for(int i = 1; i <= m; ++i)
            cin >> edge[i].u >> edge[i].v >> edge[i].w;
        cout << "Case #" << cnt++ << " : ";
        Kruskal();
    }
    return 0;
}