luogu1501 [国家集训队]Tree II

lct裸题

#include <iostream>
#include <cstdio>
using namespace std;
typedef long long ll;
int n, m, uu, vv, val[100005], tagm[100005], taga[100005], sum[100005], siz[100005];
int rev[100005], ww, xx, ch[100005][2], fa[100005];
char ss[15];
const int mod=51061;
bool isRoot(int x){
	return ch[fa[x]][0]!=x && ch[fa[x]][1]!=x;
}
bool getW(int x){
	return ch[fa[x]][1]==x;
}
void pushMul(int x, int k){
	sum[x] = (ll)sum[x] * k % mod;
	val[x] = (ll)val[x] * k % mod;
	tagm[x] = (ll)tagm[x] * k % mod;
	taga[x] = (ll)taga[x] * k % mod;
}
void pushAdd(int x, int k){
	sum[x] = (sum[x] + (ll)siz[x]*k) % mod;
	val[x] = (val[x] + k) % mod;
	taga[x] = (taga[x] + k) % mod;
}
void pushDown(int x){
	if(tagm[x]!=1){
		pushMul(ch[x][0], tagm[x]);
		pushMul(ch[x][1], tagm[x]);
		tagm[x] = 1;
	}
	if(tagm[x]){
		pushAdd(ch[x][0], taga[x]);
		pushAdd(ch[x][1], taga[x]);
		taga[x] = 0;
	}
	if(rev[x]){
		swap(ch[x][0], ch[x][1]);
		rev[ch[x][0]] ^= 1;
		rev[ch[x][1]] ^= 1;
		rev[x] = 0;
	}
}
void xf(int x){
	if(!isRoot(x))	xf(fa[x]);
	pushDown(x);
}
void upd(int x){
	siz[x] = siz[ch[x][0]] + siz[ch[x][1]] + 1;
	sum[x] = (sum[ch[x][0]] + sum[ch[x][1]] + val[x]) % mod;
}
void rotate(int x){
	int old=fa[x], oldf=fa[old], w=getW(x);
	if(!isRoot(old))	ch[oldf][ch[oldf][1]==old] = x;
	ch[old][w] = ch[x][w^1]; ch[x][w^1] = old;
	fa[ch[old][w]] = old; fa[ch[x][w^1]] = x; fa[x] = oldf;
	upd(old); upd(x);
}
void splay(int x){
	xf(x);
	while(!isRoot(x)){
		int f=fa[x];
		if(!isRoot(f))	rotate(getW(f)==getW(x)?f:x);
		rotate(x);
	}
}
void access(int x){
	int y=0;
	while(x){
		splay(x);
		ch[x][1] = y;
		upd(x);
		y = x;
		x = fa[x];
	}
}
void makeRoot(int x){
	access(x);
	splay(x);
	rev[x] ^= 1;
}
void link(int u, int v){
	makeRoot(u);
	fa[u] = v;
}
void splitLine(int u, int v){
	makeRoot(u);
	access(v);
	splay(v);
}
void cut(int u, int v){
	splitLine(u, v);
	ch[v][0] = fa[u] = 0;
}
int main(){
	cin>>n>>m;
	for(int i=1; i<=n; i++)
		tagm[i] = val[i] = siz[i] = 1;
	for(int i=1; i<n; i++){
		scanf("%d %d", &uu, &vv);
		link(uu, vv);
	}
	while(m--){
		scanf("%s", ss);
		if(ss[0]=='+'){
			scanf("%d %d %d", &uu, &vv, &ww);
			splitLine(uu, vv);
			pushAdd(vv, ww);
		}
		else if(ss[0]=='-'){
			scanf("%d %d %d %d", &uu, &vv, &ww, &xx);
			cut(uu, vv);
			link(ww, xx);
		}
		else if(ss[0]=='*'){
			scanf("%d %d %d", &uu, &vv, &ww);
			splitLine(uu, vv);
			pushMul(vv, ww);
		}
		else{
			scanf("%d %d", &uu, &vv);
			splitLine(uu, vv);
			printf("%d\n", sum[vv]);
		}
	}
	return 0;
}