洛谷P1486 [NOI2004]郁闷的出纳员

Code：

#include<cstdio>
#include<algorithm>
using namespace std;
struct Node{
    int s,val,tag,v;
    Node *ch[2];
    Node(int u){
        s=1,val=1,tag=0,v=u;
        ch[0]=ch[1]=NULL;
    }
    int cmp(int x,int ty){
        if(ty==0){
            if(x<v)return 0;if(x==v)return -1;return 1;
        }
        else{
            int lsize=ch[0]==NULL?0:ch[0]->s;
            if(x<=lsize)return 0;if(x<=lsize+val)return -1;return 1;
        }
    }
    int ls(){if(ch[0]==NULL)return 0;return ch[0]->s;}
    void maintain(){
        s=val;
        if(ch[0]!=NULL)s+=ch[0]->s;
        if(ch[1]!=NULL)s+=ch[1]->s;
    }
    void push_down(){
        if(tag!=0){
            if(ch[0]!=NULL)ch[0]->tag+=tag;
            if(ch[1]!=NULL)ch[1]->tag+=tag;
            v+=tag,tag=0;
        }
    }
};
void rotate(Node* &o,int d){
    Node *k=o->ch[d^1];o->ch[d^1]=k->ch[d];k->ch[d]=o;
    o->maintain();k->maintain();o=k;
}
void splay(Node* &o,int x,int ty){
    o->push_down();
    int d=o->cmp(x,ty);
    if(ty==1&&d==1)x-=o->ls()+o->val;
    if(d!=-1){
        Node *p=o->ch[d];
        p->push_down();
        int d2=p->cmp(x,ty);
        if(ty==1&&d2==1)x-=p->ls()+p->val;
        if(d2!=-1){
            splay(p->ch[d2],x,ty);
            if(d==d2)
                rotate(o,d^1);
            else
                rotate(o->ch[d],d2^1);
        }
        rotate(o,d^1);
    }
}
void insert(Node* &o,int x){
    if(o==NULL){
        o=new Node(x);return;
    }
    o->push_down();
    int d=o->cmp(x,0);
    if(d==-1){
        ++(o->val);++(o->s);return;
    }
    insert(o->ch[d],x);
    o->maintain();
}
int minn;
void qianqu(Node *o,int k){
    if(o==NULL)return;
    o->push_down();
    int d=o->cmp(k,0);
    if(d<1)
        qianqu(o->ch[0],k);
    else{
        minn=max(minn,o->v);
        qianqu(o->ch[1],k);
    }
}
Node *head;
int main()
{
    int n,minv,cnt_leave=0;
    scanf("%d%d",&n,&minv);
    for(int i=1;i<=n;++i)
    {
        char A[4];int k;
        scanf("%s",A);scanf("%d",&k);
        if(A[0]=='I'){
            if(k>=minv){
                insert(head,k);
                splay(head,k,0);
            }
            //else ++cnt_leave;
        }
        if(A[0]=='A'&&head!=NULL)head->tag+=k;
        if(A[0]=='S'&&head!=NULL){
            head->tag-=k;minn=-1000000;
            qianqu(head,minv);
            if(minn!=-1000000){
                splay(head,minn,0);
                cnt_leave+=head->ls()+head->val;
                if(head->ch[1]!=NULL)head=head->ch[1];
                else head=NULL;
            }
        }
        if(A[0]=='F'){
            int tot=head==NULL?0:head->s;
            if(k>tot)printf("-1\n");
            else{
                splay(head,tot-k+1,1);
                printf("%d\n",head->v);
            }
        }
    }
    printf("%d\n",cnt_leave);
    return 0;
}