HDU3487 Play With Chains(Splay)

很裸的Splay,抄一下CLJ的模板当作复习，debug了一个下午，收获是终于搞懂了以前看这个模板里不懂的内容。以前用这个模板的时候没有看懂为什么get函数返回的前缀要加个引用，经过一下午的debug终于明白，如果加了引用的时候是会被修改到的，删除实际上就是将root->ch[1]->ch[0]置为null，但由于我们还要把这一段插回去，所以get的时候的t前面没有加引用，否则一旦置为null的话 t也会变为null。还有就是这次是第一次用这个模板进行插入，本题倒腾了很久就是在这个插入上，没有找到合适的姿势。经过摸索一个正确的姿势是在  1 2 3 4 5 ... n 的第k个位置后插入，应该是先get(k+1,k+1),然后直接在root->ch[1]里设置左儿子即可。复习Splay是为了学习LCT做准备吧。。－ －0

#pragma warning(disable:4996)

#include <iostream>

#include <cstring>

#include <string>

#include <cstdio>

#include <vector>

#include <algorithm>

#include <map>

using namespace std;



#define ll long long

#define maxn 350000



struct Node

{

	Node *ch[2], *p;

	int size,val;

	int rev;

	Node(){ size = 0; val = 0; rev = 0; }

	bool d(){

		return this == p->ch[1];

	}

	void setc(Node *c, int d){

		ch[d] = c; c->p = this;

	}

	void relax();

	void revIt()

	{

		rev ^= 1;

	}

	void upd(){

		size = ch[0]->size + ch[1]->size + 1;

	}

}Tnull,*null=&Tnull;



Node mem[maxn], *C = mem;



void Node::relax()

{

	if (rev){

		swap(ch[0], ch[1]);

		for (int i = 0; i < 2; i++){

			if (ch[i] != null) ch[i]->revIt();

		}

		rev = 0;

	}

}



Node *make(int v)

{

	C->ch[0] = C->ch[1] = null;

	C->size = 1; C->val = v; C->rev = 0;

	return C++;

}



Node* build(int l, int r)

{

	if (l >= r) return null;

	int m = (l + r) >> 1;

	Node *t = make(m);

	t->setc(build(l, m), 0);

	t->setc(build(m + 1, r), 1);

	t->upd();

	return t;

}



Node *root;



void rot(Node *t)

{

	Node *p = t->p;

	p->relax();

	t->relax();

	int d = t->d();

	p->p->setc(t, p->d());

	p->setc(t->ch[!d], d);

	t->setc(p, !d);

	p->upd();

	if (p == root) root = t;

}



void splay(Node *t, Node *f = null)

{

	while (t->p != f){

		if (t->p->p == f) rot(t);

		else t->d() == t->p->d() ? (rot(t->p), rot(t)) : (rot(t), rot(t));

	}

	t->upd();

}



Node* select(int k) {

	for (Node*t = root;;) {

		t->relax();

		int c = t->ch[0]->size;

		if (k == c)

			return t;

		if (k > c)

			k -= c + 1, t = t->ch[1];

		else

			t = t->ch[0];

	}

}



Node*&get(int l, int r) { //[l,r)

	Node*L = select(l - 1);

	Node*R = select(r);

	splay(L);

	splay(R, L);

	return R->ch[0];

}



int n, m;



int main()

{

	while (cin >> n >> m)

	{

		if (n <0 && m <0) break;

		memset(mem, 0, sizeof(mem));

		C = mem;

		root = build(0, n + 2); root->p = null;

		char oper[10];

		int li, ri, wi;

		for (int i = 0; i < m; i++){

			scanf("%s", oper);

			if (oper[0] == 'C'){

				scanf("%d%d%d", &li, &ri, &wi);

				Node *t = get(li, ri + 1);

				root->ch[1]->ch[0] = null;

				splay(root->ch[1]);

				Node *&x = get(wi+1, wi+1);

				root->ch[1]->setc(t, 0);

			}

			else{

				scanf("%d%d", &li, &ri);

				Node *&t = get(li, ri + 1);

				t->revIt();

				splay(t);

			}

		}

		for (int i = 1; i <= n; i++){

			if (i >= 2) printf(" ");

			Node *&t = get(i, i + 1);

			printf("%d", t->val);

		}

		puts("");

	}

	return 0;

}