【动态树】 HDOJ 5398 GCD Tree

LCT维护最大生成树。。。。。然而这种题目比赛的时候根本不敢写。。。

#include <bits/stdc++.h>
using namespace std;

#define mp(x, y) make_pair(x, y)
const int maxn = 100005;
const int maxm = 300005;
const int INF = 0x3f3f3f3f * 2;

struct node *null;
struct node
{
	int size, rev, t1, t2;
       	pair<int, node*> Min, cMin;
	node *fa, *ch[2];

	void init()
	{
		size = rev = 0;
		fa = ch[0] = ch[1] = null;
	}

	inline bool d()
	{
		return fa->ch[1] == this;
	}

	inline bool isroot()
	{
		return fa == null || fa->ch[0] != this && fa->ch[1] != this;
	}

	inline void setc(node *p, int d)
	{
		ch[d] = p;
		p->fa = this;
	}

	inline void pushup()
	{
		size = ch[0]->size + ch[1]->size + 1;
		Min = cMin;
		if(ch[0] != null) Min = min(Min, ch[0]->Min);
		if(ch[1] != null) Min = min(Min, ch[1]->Min);
	}

	inline void flip()
	{
		if(this == null) return;
		swap(ch[0], ch[1]);
		rev ^= 1;
	}
	
	inline void pushdown()
	{
		if(rev) {
			ch[0]->flip();
			ch[1]->flip();
			rev = 0;
		}
	}

	inline void go()
	{
		if(!isroot()) fa->go();
		pushdown();
	}

	void rot()
	{
		node *f = fa, *ff = fa->fa;
		int c = d(), cc = fa->d();
		f->setc(ch[!c], c);
		this->setc(f, !c);
		if(ff->ch[cc] == f) ff->setc(this, cc);
		else this->fa = ff;
		f->pushup();
	}

	node* splay()
	{
		go();
		while(!isroot()) {
			if(!fa->isroot()) d() == fa->d() ? fa->rot() : rot();
			rot();
		}
		pushup();
		return this;
	}

	node* access()
	{
		for(node *p = this, *q = null; p != null; q = p, p = p->fa) {
			p->splay()->setc(q, 1);
			p->pushup();
		}
		return splay();
	}

	inline void makeroot()
	{
		access()->flip();
	}

	node* getroot() {
		node *x;
		for(x = access(); x->pushdown(), x->ch[0] != null; x = x->ch[0]);
		return x;
	}

	void cut()
	{
		access();
		ch[0]->fa = null;
		ch[0] = null;
		pushup();
	}

	void cut(node *o)
	{
		makeroot();
		o->cut();
	}

	void link(node *p)
	{
		makeroot();
		fa = p;
	}
}*Node[maxn], pool[maxm], *tail;

int res[maxn];
vector<int> vec[maxn];
int n;

pair<int, node*> query(node *a, node *b)
{
	a->access();
	for(a = null; b != null; a = b, b = b->fa) {
		b->splay();
		if(b->fa == null) return min(b->ch[1]->Min, a->Min);
		b->setc(a, 1);
		b->pushup();
	}
}

node* newnode()
{
	node *p = tail++;
	p->fa = p->ch[0] = p->ch[1] = null;
	p->size = p->rev = 0;
	p->Min = p->cMin = mp(INF, p);
	return p;
}

void init()
{
	tail = pool;
	null = newnode();
	for(int i = 1; i <= n; i++) Node[i] = newnode();
	
	for(int i = n; i >= 1; i--) 
		for(int j = i + i; j <= n; j += i)
			vec[j].push_back(i);

	int ans = 0;
	for(int i = 2; i <= n; i++) {
		int t = vec[i][0];
		node *p = newnode();
		p->t1 = i, p->t2 = t;
		p->cMin = p->Min = mp(t, p);
		p->link(Node[i]);
		p->link(Node[t]);
		ans += t;
		
		for(int j = 1; j < vec[i].size(); j++) {
			t = vec[i][j];
			pair<int, node*> tpair = query(Node[i], Node[t]);
			if(tpair.first >= t) continue;
			ans -= tpair.first;
			ans += t;
			
			p = tpair.second;
			
			int t1 = p->t1;
			int t2 = p->t2;
			
			p->cut(Node[t1]);
			p->cut(Node[t2]);
			
			p->init();
			p->t1 = i, p->t2 = t;
			p->Min = p->cMin = mp(t, p);
			p->link(Node[i]);
			p->link(Node[t]);
		}		
		res[i] = ans;
	}
}

int main()
{
	n = 100000;
	init();
	int t;
	while(scanf("%d", &t) != EOF) {
		printf("%d\n", res[t]);
	}
	
	return 0;
}


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