BZOJ1503(Splay)

题目：http://www.lydsy.com/JudgeOnline/problem.php?id=1503

 

#include <iostream>#include <string.h>#include <stdio.h>using namespace std;struct Node{    int val,size,cnt,lazy;    Node *pre,*ch[2];    Node()    {        size = lazy = cnt = 0;    }};Node *null,*root,*newNode,*last;void Init()      //新增的newNode为root的父亲节点{    null = new(Node);    root = null;    newNode = new(Node);    newNode->ch[0] = root;    newNode->ch[1] = null;    root->pre = newNode;}void Update(Node* &t){    t->size = t->cnt + t->ch[0]->size + t->ch[1]->size;    t->ch[0]->pre = t->ch[1]->pre = t;}int F(Node *t)    // 判断当前点的是左孩子还是右孩子{    return t->pre->ch[1] == t;}void Rotate(Node* t,int c){    Node *k = t->ch[c];    k->pre = t->pre;    t->pre->ch[F(t)] = k;    t->ch[c] = k->ch[!c];    k->ch[!c] = t;    Update(t);    Update(k);}void Splay(Node* last,Node* newNode){    Node *tmp = last;    while(tmp->pre != newNode)    {        if(tmp->pre->pre == newNode)            Rotate(tmp->pre,F(tmp));        else if(F(tmp->pre) == F(tmp))        {            Rotate(tmp->pre->pre,F(tmp->pre));            Rotate(tmp->pre,F(tmp));        }        else        {            Rotate(tmp->pre,F(tmp));            Rotate(tmp->pre,F(tmp));        }    }    root = newNode->ch[0];}void PushDown(Node* &t){    t->ch[0]->val += t->lazy;    t->ch[0]->lazy += t->lazy;    t->ch[1]->val += t->lazy;    t->ch[1]->lazy += t->lazy;    t->lazy = 0;}void Insert(Node* &t,int x){    if(t == null)    {        t=new(Node);        t->val = x;        t->ch[0] = t->ch[1] = null;        t->size = t->cnt = 1;        last = t;        return;    }    PushDown(t);    if(t->val == x) t->cnt++;    if(t->val > x)  Insert(t->ch[0],x);    if(t->val < x)  Insert(t->ch[1],x);    Update(t);}Node *Find(Node *t,int x)  //查找后继，包括等于自己{    if(t == null) return null;    PushDown(t);    if(t->val == x) return t;    if(t->val < x)  return Find(t->ch[1],x);    if(t->val > x)    {        Node *tmp = Find(t->ch[0],x);        if(tmp != null) return tmp;        else return t;    }}int Query(Node *t,int k)    //询问第K大{    if(t == null) return -1;    PushDown(t);    if(t->ch[1]->size >= k) return Query(t->ch[1],k);    if(t->ch[1]->size + t->cnt >= k) return t->val;    return Query(t->ch[0],k - t->ch[1]->size - t->cnt);}void Work(){    int n,limit;    scanf("%d%d%*c",&n,&limit);    int x,ans = 0;    while(n--)    {        char c;        scanf("%c %d%*c",&c,&x);        if(c == 'I'&&x < limit) continue;        if(c == 'I')        {            Insert(newNode->ch[0],x);            Update(newNode);            Splay(last,newNode);        }        else if(c == 'A')        {            root->val += x;            root->lazy += x;        }        else if(c == 'S')        {            last = null;            last = Find(root,limit + x);            if(last == null)            {                ans += root->size;                root = null;                newNode->ch[0] = root;                Update(newNode);            }            else            {                Splay(last,newNode);                ans += root->ch[0]->size;                root->ch[0] = null;                root->val -= x;                root->lazy -= x;                Update(root);            }        }        else if(c == 'F')            printf("%d\n",Query(root,x));    }    printf("%d\n",ans);}int main(){    Init();    Work();    return 0;}