$Noip2013/Luogu1967$ 货车运输 最大生成树+倍增$lca$

#include<bits/stdc++.h>
#define il inline
#define Rg register
#define go(i,a,b) for(Rg int i=a;i<=b;++i)
#define yes(i,a,b) for(Rg int i=a;i>=b;--i)
#define e(i,u) for(Rg int i=b[u];i;i=a[i].nt)
#define mem(a,b) memset(a,b,sizeof(a))
#define ll long long
#define db double
#define inf 2147483647
using namespace std;
il int read()
{
    Rg int x=0,y=1;char c=getchar();
    while(c<‘0‘||c>‘9‘){if(c==‘-‘)y=-1;c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){x=(x<<1)+(x<<3)+c-‘0‘;c=getchar();}
    return x*y;
}
const int N=10010;
int n,m,q,f[N],b[N],ct,c[N][11],d[N][11],dep[N];
bool vis[N];
struct node{int u,v,w;}eg[N*5];
struct node1{int v,w,nt;}a[N*10];
il bool cmp(node x,node y){return x.w>y.w;}
il int find(int x){if(x==f[x])return x;return f[x]=find(f[x]);}
il void add(int u,int v,int w){a[++ct]=(node1){v,w,b[u]};b[u]=ct;}
il void dfs(int u)
{
    vis[u]=1;
    e(i,u)
    {
        Rg int v=a[i].v,w=a[i].w;
        if(vis[v])continue;
        dep[v]=dep[u]+1;c[v][0]=u;d[v][0]=w;
        go(j,1,10)c[v][j]=c[c[v][j-1]][j-1],d[v][j]=min(d[v][j-1],d[c[v][j-1]][j-1]);
        dfs(v);
    }
}
il int sol(int u,int v)
{
    Rg int ret=inf;
    if(dep[u]<dep[v])swap(u,v);
    yes(j,10,0)
    {
        if(dep[c[u][j]]>dep[v])ret=min(ret,d[u][j]),u=c[u][j];
    }
    if(dep[u]>dep[v])ret=min(ret,d[u][0]),u=c[u][0];
    if(u==v)return ret;
    yes(j,10,0)if(c[u][j]!=c[v][j])ret=min(ret,min(d[u][j],d[v][j])),u=c[u][j],v=c[v][j];
    ret=min(ret,min(d[u][0],d[v][0]));
    return ret;
}
int main()
{
    n=read(),m=read();
    go(i,1,n)f[i]=i;
    go(i,1,m)eg[i]=(node){read(),read(),read()};
    sort(eg+1,eg+m+1,cmp);
    go(i,1,m)
    {
        Rg int u=eg[i].u,v=eg[i].v,w=eg[i].w;
        if(find(u)==find(v))continue;
        f[find(u)]=find(v);
        add(u,v,w),add(v,u,w);
    }
    go(i,1,n)if(!vis[i])dep[i]=1,dfs(i);
    q=read();
    while(q--)
    {
        Rg int u=read(),v=read();
        if(find(u)!=find(v))printf("-1\n");
        else printf("%d\n",sol(u,v));//cout<<endl;
    }
    return 0;
}