loj2049 「HNOI2016」网络

好像复杂度来说不是正解……不加谜之优化（下叙）能被loj上的加强数据卡

#include <algorithm>
#include <iostream>
#include <cstdio>
#include <vector>
using namespace std;
int n, m, hea[100005], cnt, uu[200005], fa[100005], siz[100005], son[100005], idx;
int dfn[100005], top[100005], opt, vv[200005], ww[200005], dep[100005], xx, ans;
struct Edge{
	int too, nxt;
}edge[200005], lian[100005];
struct SGTNode{
	vector<int> vec1, vec2;
	void insert(int x){
		vec1.push_back(x);
		push_heap(vec1.begin(), vec1.end());
	}
	void shanchu(int x){
		vec2.push_back(x);
		push_heap(vec2.begin(), vec2.end());
	}
	int getTop(){
		while(true){
			if(!vec1.size())	return -1;
			if(!vec2.size())	return vec1[0];
			if(vec1[0]==vec2[0]){
				pop_heap(vec1.begin(), vec1.end());
				vec1.pop_back();
				pop_heap(vec2.begin(), vec2.end());
				vec2.pop_back();
			}
			else	return vec1[0];
		}
	}
};
struct SGT{
	SGTNode nd[400005];
	void update(int o, int l, int r, int x, int y, int w){
		if(l>=x && r<=y){
			if(opt==0)	nd[o].insert(w);
			else	nd[o].shanchu(w);
		}
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			if(x<=mid)	update(lson, l, mid, x, y, w);
			if(mid<y)	update(rson, mid+1, r, x, y, w);
		}
	}
	void query(int o, int l, int r, int x){
		ans = max(ans, nd[o].getTop());
		if(l==r)	;
		else{
			int mid=(l+r)>>1;
			int lson=o<<1;
			int rson=lson|1;
			if(x<=mid)	query(lson, l, mid, x);
			else	query(rson, mid+1, r, x);
		}
	}
}sgt;
bool cmp(const Edge &u, const Edge &v){
	return u.too<v.too;
}
void add_edge(int fro, int too){
	edge[++cnt].nxt = hea[fro];
	edge[cnt].too = too;
	hea[fro] = cnt;
}
void dfs1(int x, int f){
	fa[x] = f;
	dep[x] = dep[f] + 1;
	siz[x] = 1;
	int maxSon=-1;
	for(int i=hea[x]; i; i=edge[i].nxt){
		int t=edge[i].too;
		if(t!=f){
			dfs1(t, x);
			siz[x] += siz[t];
			if(siz[t]>=maxSon){//就是这里，要写\geq……
				maxSon = siz[t];
				son[x] = t;
			}
		}
	}
}
void dfs2(int x, int topf){
	dfn[x] = ++idx;
	top[x] = topf;
	if(!son[x])	return ;
	dfs2(son[x], topf);
	for(int i=hea[x]; i; i=edge[i].nxt){
		int t=edge[i].too;
		if(t!=fa[x] && t!=son[x])
			dfs2(t, t);
	}
}
void rangeUpdate(int u, int v, int w){
	int faq=0;
	while(top[u]!=top[v]){
		if(dep[top[u]]<dep[top[v]])	swap(u, v);
		lian[++faq] = (Edge){dfn[top[u]], dfn[u]};
		u = fa[top[u]];
	}
	if(dep[u]>dep[v])	swap(u, v);
	lian[++faq] = (Edge){dfn[u], dfn[v]};
	sort(lian+1, lian+1+faq, cmp);
	int lst=0;
	for(int i=1; i<=faq; i++){
		if(lst+1<=lian[i].too-1)
			sgt.update(1, 1, n, lst+1, lian[i].too-1, w);
		lst = lian[i].nxt;
	}
	if(lst+1<=n)
		sgt.update(1, 1, n, lst+1, n, w);
}
int main(){
	cin>>n>>m;
	for(int i=1; i<n; i++){
		scanf("%d %d", &xx, &ans);
		add_edge(xx, ans);
		add_edge(ans, xx);
	}
	dfs1(1, 0);
	dfs2(1, 1);
	for(int i=1; i<=m; i++){
		scanf("%d", &opt);
		if(opt==0){
			scanf("%d %d %d", &uu[i], &vv[i], &ww[i]);
			rangeUpdate(uu[i], vv[i], ww[i]);
		}
		else if(opt==1){
			scanf("%d", &xx);
			rangeUpdate(uu[xx], vv[xx], ww[xx]);
		}
		else{
			scanf("%d", &xx);
			ans = -1;
			sgt.query(1, 1, n, dfn[xx]);
			printf("%d\n", ans);
		}
	}
	return 0;
}