P1486 [NOI2004]郁闷的出纳员

思路

平衡树的题目
题目中的全部减少可以通过维护全局的减少量S（不过我使用了打tag的方式），然后每次插入的时候插入\(v_i-S\)，删除的时候直接在平衡树上二分移除对应的子树即可

代码

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
using namespace std;
int Nodecnt=0,root,n,lim;
struct Node{
    int lson,rson,sz,val,ran,add,times;
}Treap[100100*2];
queue<int> q;
void throwin(int x){
    q.push(x);
}
int getnew(int val){
    int o;
    if(q.size())
        o=q.front(),q.pop();
    else
        o=++Nodecnt;
    Treap[o].lson=Treap[o].rson=0;
    Treap[o].sz=Treap[o].times=1;
    Treap[o].ran=rand();
    Treap[o].val=val;
    Treap[o].add=0;
    return o;
}
void pushup(int o){
    Treap[o].sz=Treap[Treap[o].lson].sz+Treap[Treap[o].rson].sz+Treap[o].times;
}
void pushdown(int o){
    if(Treap[o].add){
        Treap[Treap[o].lson].val+=Treap[o].add;
        Treap[Treap[o].rson].val+=Treap[o].add;
        Treap[Treap[o].lson].add+=Treap[o].add;
        Treap[Treap[o].rson].add+=Treap[o].add;
        Treap[o].add=0;
    }
}
void rorateL(int &o){
    int x=Treap[o].rson;
    pushdown(o);
    pushdown(x);
    Treap[o].rson=Treap[x].lson;
    Treap[x].lson=o;
    pushup(o);
    pushup(x);
    o=x;
}
void rorateR(int &o){
    int x=Treap[o].lson;
    pushdown(o);
    pushdown(x);
    Treap[o].lson=Treap[x].rson;
    Treap[x].rson=o;
    pushup(o);
    pushup(x);
    o=x;
}
void insert(int val,int &o){
    if(!o){
        o=getnew(val);
        return;
    }
    pushdown(o);
    Treap[o].sz++;
    if(val<Treap[o].val){
        insert(val,Treap[o].lson);
        if(Treap[Treap[o].lson].ran<Treap[o].ran)
            rorateR(o);
    }
    else if(val>Treap[o].val){
        insert(val,Treap[o].rson);
        if(Treap[Treap[o].rson].ran<Treap[o].ran)
            rorateL(o);
    }
    else{
        Treap[o].times++;
    }
}
void del(int val,int &o){
    if(o==0)
        return;
    pushdown(o);
    if(Treap[o].val==val){
        Treap[o].lson=0;
        pushup(o);
        return;
    }
    else if(Treap[o].val<val&&Treap[o].rson){
        rorateL(o);
        del(val,o);
        pushup(o);
        return;
    }
    else if(Treap[o].val<val){
        o=0;
        return;
    }
    else if(Treap[o].val>val){
        del(val,Treap[o].lson);
        pushup(o);
        return;
    }
}
int query(int val,int o){
    if(!o)
        return -1;
    pushdown(o);
    if(val>=Treap[Treap[o].rson].sz+1&&val<=Treap[Treap[o].rson].sz+Treap[o].times)
        return Treap[o].val;
    else if(val>Treap[Treap[o].rson].sz+Treap[o].times)
        return query(val-Treap[Treap[o].rson].sz-Treap[o].times,Treap[o].lson);
    else
        return query(val,Treap[o].rson);
}
int main(){
    int cnt=0;
    scanf("%d %d",&n,&lim);
    for(int i=1;i<=n;i++){
        char c=getchar();
        while(c!='I'&&c!='A'&&c!='S'&&c!='F')
            c=getchar();
        if(c=='I'){
            int k;
            scanf("%d",&k);
            if(k<lim){
                // cnt++;
                continue;
            }
            insert(k,root);
        }
        else if(c=='A'){
            int k;
            scanf("%d",&k);
            Treap[root].val+=k;
            Treap[root].add+=k;
            pushdown(root);
        }
        else if(c=='S'){
            int k,t;
            scanf("%d",&k);
            Treap[root].val-=k;
            Treap[root].add-=k;
            pushdown(root);
            int tmp=Treap[root].sz;
            del(lim,root);
            cnt+=tmp-Treap[root].sz;
        }
        else{
            int k;
            scanf("%d",&k);
            printf("%d\n",query(k,root));
        }
    }
    printf("%d\n",cnt);
    return 0;
}