BZOJ 3732 Network

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn=30009;

int n,m,T;

struct Edge{
	int u,v,d;
}edges[maxn];
bool cmp(const Edge &rhs1,const Edge &rhs2){
	return rhs1.d<rhs2.d;
}
int father[maxn];
int Getf(int x){
	if(father[x]==x)return x;
	return father[x]=Getf(father[x]);
}
void Unionn(int x,int y){
	int fx=Getf(x);
	int fy=Getf(y);
	if(fx!=fy)father[fx]=fy;
}

int cntedge;
int head[maxn];
int to[maxn<<1],nex[maxn<<1],dist[maxn];
void Addedge(int x,int y,int z){
	nex[++cntedge]=head[x];
	to[cntedge]=y;
	dist[cntedge]=z;
	head[x]=cntedge;
}

int f[maxn][20],g[maxn][20],dep[maxn];
void Dfs(int now,int fa){
	dep[now]=dep[fa]+1;
	for(int i=head[now];i;i=nex[i]){
		if(to[i]==fa)continue;
		f[to[i]][0]=now;
		g[to[i]][0]=dist[i];
		Dfs(to[i],now);
	}
}
void LCAinit(){
	for(int j=1;j<=19;++j){
		for(int i=1;i<=n;++i){
			f[i][j]=f[f[i][j-1]][j-1];
			g[i][j]=max(g[i][j-1],g[f[i][j-1]][j-1]);
		}
	}
}
int GetMaxd(int u,int v){
	int ret=0;
	if(dep[u]<dep[v])swap(u,v);
	for(int j=19;j>=0;--j){
		if(dep[f[u][j]]>=dep[v]){
			ret=max(ret,g[u][j]);
			u=f[u][j];
		}
	}
	if(u==v)return ret;
	for(int j=19;j>=0;--j){
		if(f[u][j]!=f[v][j]){
			ret=max(ret,max(g[u][j],g[v][j]));
			u=f[u][j];v=f[v][j];
		}
	}
	return max(ret,max(g[u][0],g[v][0]));
}

int main(){
	scanf("%d%d%d",&n,&m,&T);
	for(int i=1;i<=m;++i)scanf("%d%d%d",&edges[i].u,&edges[i].v,&edges[i].d);
	sort(edges+1,edges+1+m,cmp);
	for(int i=1;i<=n;++i)father[i]=i;
	for(int i=1;i<=m;++i){
		int u=edges[i].u;
		int v=edges[i].v;
		int d=edges[i].d;
		if(Getf(u)==Getf(v))continue;
		Unionn(u,v);
		Addedge(u,v,d);
		Addedge(v,u,d);
	}
	
	Dfs(1,0);
	LCAinit();
//	
//	for(int i=1;i<=n;++i){
//		printf("%d %d\n",f[i][0],g[i][0]);
//	}
	
	while(T--){
		int x,y;
		scanf("%d%d",&x,&y);
		printf("%d\n",GetMaxd(x,y));
	}
	return 0;
}