BZOJ 1208 HNOI2004 宠物收养所 平衡树/set

题目大意：有一家宠物收养所，有没有被收养的宠物或者是想收养宠物的人，每个宠物有一个个性值，每个想收养宠物的人有一个理想的个性值。每一个时刻，宠物收养所里只能有想收养宠物的人或宠物。当人领走宠物时，就会有一个不满意度。求这个最小的不满意度。

思路：就是个模拟+数据结构维护。用set可以水过，时间卡的不是很紧。练手写了Treap。注意极大值不能开太大，会re

CODE：

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define INF 0x3f3f3f3f
using namespace std;

struct Complex{
	int val,random,cnt,size;
	Complex *son[2];

	Complex() {
		son[0] = son[1] = NULL;
		random = rand();
		cnt = size = 1;
	}
	void Maintain() {
		size = cnt;
		if(son[0] != NULL)	size += son[0]->size;
		if(son[1] != NULL)	size += son[1]->size;
	}
	int Compare(int x) {
		if(x == val)	return -1;
		return x > val;
	}
}*root; 

int cnt,ans;
int total;

int flag;

inline void Rotate(Complex *&a,bool dir);
void Insert(Complex *&a,int x);
void Delete(Complex *&a,int x);
int FindSucc(Complex *a,int x);
int FindPred(Complex *a,int x);

int main()
{
	cin >> cnt;
	for(int x,i = 1;i <= cnt; ++i) {
		scanf("%d%d",&flag,&x);
		if(total > 0) {
			if(flag)	Insert(root,x),total++;
			else {
				int pred = FindPred(root,x);
				int succ = FindSucc(root,x);
				int will_delete = (x - pred <= succ - x) ? pred:succ;
				Delete(root,will_delete);
				total--;
				ans += abs(will_delete - x);
			}
		}
		else if(total < 0) {
			if(!flag)	Insert(root,x),total--;
			else {
				int pred = FindPred(root,x);
				int succ = FindSucc(root,x);
				int will_delete = (x - pred <= succ - x) ? pred:succ;
				Delete(root,will_delete);
				total++;
				ans += abs(will_delete - x);
			}
		}
		else	Insert(root,x),total = (flag ? 1:-1);
		ans %= 1000000;
	}
	cout << ans << endl;
	return 0;
}

inline void Rotate(Complex *&a,bool dir)
{
	Complex *k = a->son[!dir];
	a->son[!dir] = k->son[dir];
	k->son[dir] = a;
	a->Maintain(),k->Maintain();
	a = k;
}

void Insert(Complex *&a,int x)
{
	if(a == NULL) {
		a = new Complex();
		a->val = x;
		return ;
	}
	int dir = a->Compare(x);
	if(dir == -1)
		a->cnt++;
	else {
		Insert(a->son[dir],x);
		if(a->son[dir]->random > a->random)
			Rotate(a,!dir);
	}
	a->Maintain();
}

void Delete(Complex *&a,int x)
{
	int dir = a->Compare(x);
	if(dir != -1)
		Delete(a->son[dir],x);
	else {
		if(a->cnt > 1)
			a->cnt--;
		else {
			if(a->son[0] == NULL)	a = a->son[1];
			else if(a->son[1] == NULL)	a = a->son[0];
			else {
				bool _dir = (a->son[0]->random > a->son[1]->random);
				Rotate(a,_dir);
				Delete(a->son[_dir],x);
			}
		}
	}
	if(a != NULL)	a->Maintain();
}

int FindPred(Complex *a,int x)
{
	if(a == NULL)	return -INF;
	if(a->val > x)	return FindPred(a->son[0],x);
	return max(a->val,FindPred(a->son[1],x));
}

int FindSucc(Complex *a,int x)
{
	if(a == NULL)	return INF;
	if(a->val < x)	return FindSucc(a->son[1],x);
	return min(a->val,FindSucc(a->son[0],x));
}