NOIP 2013 Day1 T3 货车运输

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace std;
struct data
{
    int x,y,z;
};
    data tr[50005];
struct node
{
    int l,w;
};
    node tt;
vector  te[10005];
int n,m,a,b,c,q,k=1;
int fa[10005],dep[10005],dis[10005][25],f[10005][25];
bool vis[10005];
bool comp(data a,data b)
{
    if (a.z>=b.z)  return true;
    return false;
}
int find (int x){
    if (fa[x]==x)  return x;
    else {
        fa[x]=find(fa[x]);
        return fa[x];
    }
}
void kruskal(){
    for (int i=1;i<=m;i++)
    {
        int r1=find(tr[i].x);
        int r2=find(tr[i].y);
        if (r2!=r1){
            fa[r2]=r1;//here
            tt.l=tr[i].y;tt.w=tr[i].z;
            te[tr[i].x].push_back(tt);
            tt.l=tr[i].x;tt.w=tr[i].z;
            te[tr[i].y].push_back(tt);
        }
    }
}
void dfs(int x)
{
    vis[x]=true;
    for (int i=0;idep[y])  swap(x,y);
    int h=dep[y]-dep[x];
    for (int i=0;(1<=0;i--)
            if (f[x][i]!=f[y][i])
            {
                sm=min(sm,min(dis[x][i],dis[y][i]));
                x=f[x][i];y=f[y][i];
            }
        sm=min(sm,min(dis[x][0],dis[y][0]));
        x=f[x][0];
    }
    return sm;
}
int main()
{
    freopen ("truck.in","r",stdin);
    //freopen ("truck.out","w",stdout);
    scanf ("%d%d",&n,&m);
    for (int i=1;i<=n;i++)  fa[i]=i;
    for (int i=1;i<=m;i++)
    {
        scanf ("%d%d%d",&a,&b,&c);
        tr[i].x=a;
        tr[i].y=b;
        tr[i].z=c;
    }
    sort(tr+1,tr+m+1,comp);
    kruskal();
    dep[1]=1;
    dfs(1);
    init();
    scanf ("%d",&q);
    for (int i=1;i<=q;i++)
    {
        scanf ("%d%d",&a,&b);
        if (find(a)!=find(b))  printf ("-1\n");
        else
        {
            int s=lca(a,b);
            printf ("%d\n",s);
        }
    }
    return 0;
}