洛谷P2596 [ZJOI2006]书架

指针写的代码量真心大
Code：

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxn=900000;
int key[maxn];
int D[maxn];
char A[30];
int n,m;
struct Node{
    Node *ch[2];
    int v,s,val;
    Node(int a,int b){//val:编号,v:优先级.
        val=a,v=b,s=1;
        ch[0]=ch[1]=NULL;
    }
    int cmp1(int x){ 
        if(x<v)return 0;if(x==v)return -1;return 1;
    }
    int ls(){
        if(ch[0]==NULL)return 0;return ch[0]->s;
    }
    int cmp2(int x){             //比较大小
        int lsize=ch[0]==NULL?0:ch[0]->s;
        if(x<=lsize)return 0;
        if(x==lsize+1)return -1;
        return 1;
    }
    void maintain(){
        s=1;
        if(ch[0]!=NULL)s+=ch[0]->s;
        if(ch[1]!=NULL)s+=ch[1]->s;
    }
};
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 splay1(Node* &o,int k){  //第k大
    int d=o->cmp2(k);
    if(d==1)k-=o->ls()+1;
    if(d!=-1){
        Node *p=o->ch[d];
        int d2=p->cmp2(k);
        if(d2==1)k-=p->ls()+1;
        if(d2!=-1){
            splay1(p->ch[d2],k);
            if(d==d2)rotate(o,d^1);
            else rotate(o->ch[d],d2^1);
        }
        rotate(o,d^1);
    }
}
void splay2(Node* &o,int x){
    int d=o->cmp1(x);
    if(d!=-1){
        Node *p=o->ch[d];
        int d2=p->cmp1(x);
        if(d2!=-1){
            splay2(p->ch[d2],x);
            if(d==d2)rotate(o,d^1);
            else rotate(o->ch[d],d2^1);
        }
        rotate(o,d^1);
    }
}
void build(int arr[],int l,int r,Node* &o){
    if(l>r)return;
    int mid=(l+r)/2;
    o=new Node(arr[mid],mid);
    build(arr,l,mid-1,o->ch[0]);
    build(arr,mid+1,r,o->ch[1]);
    o->maintain();
}
Node *head;
void init(){
    head=NULL;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;++i){
        int a;scanf("%d",&a);
        key[a]=i,D[i]=a;
    }
    build(D,1,n,head);
}
void remove(Node* &o){
    if(o->ch[0]==NULL)o=o->ch[1];
    else if(o->ch[1]==NULL)o=o->ch[0];
    else{
        splay1(o->ch[0],o->ch[0]->s);
        Node *left=o->ch[0];
        Node *right=o->ch[1];
        left->ch[1]=right;
        left->maintain();
        o=left;
    }
}
int main(){
   // freopen("in.txt","r",stdin);
    init();
    int maxv=n+1,minv=0;
    for(int i=1;i<=m;++i){
        int S;
        scanf("%s",A);scanf("%d",&S);
        if(A[0]=='T'){
            splay2(head,key[S]);
            remove(head);
            splay1(head,1);
            head->ch[0]=new Node(S,--minv);
            key[S]=minv;
            head->maintain();
        }
        if(A[0]=='B'){
            splay2(head,key[S]);
            remove(head);
            splay1(head,head->s);
            head->ch[1]=new Node(S,++maxv);
            key[S]=maxv;
            head->maintain();
        }
        if(A[0]=='I'){
            int t;
            scanf("%d",&t);
            if(t!=0){
                splay2(head,key[S]);
                if(t==-1){
                    splay1(head->ch[0],head->ch[0]->s);
                    swap(key[S],key[head->ch[0]->val]);
                    swap(head->val,head->ch[0]->val);
                }
                else if(t==1){
                    splay1(head->ch[1],1);
                    swap(key[S],key[head->ch[1]->val]);
                    swap(head->val,head->ch[1]->val);
                }
            }
        }
        if(A[0]=='A'){
            splay2(head,key[S]);
            printf("%d\n",head->ls());
        }
        if(A[0]=='Q'){
            splay1(head,S);
            printf("%d\n",head->val);
        }
    }
    return 0;
}