HYSBZ 1503 郁闷的出纳员 伸展树

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <string>
#include <vector>
#include <limits>
#include <algorithm>

using namespace std;

typedef long long LL;

const int Max = 100010;

const int INF = 0x3f3f3f3f;

struct SplayTree
{
    int num[Max],pre[Max],next[Max][2],key[Max];

    int root,Size;

    void PushUp(int x) //向上更新，计算以自己为根节点的树中节点的个数
    {
        num[x] = num[next[x][0]] + num[next[x][1]]+1;
    }
    void Rotate(int x,int kind)//伸展操作
    {
        int y = pre[x];
        int z = pre[y];
        next[y][!kind] = next[x][kind];
        pre[next[x][kind]] = y;
        next[z][next[z][1]==y] = x;
        pre[x] = z;
        next[x][kind] = y;
        pre[y] = x;
        PushUp(y);
        PushUp(x);
    }
    void Splay(int x,int goal)
    {
        if(x!=goal)
        {
            while(pre[x]!=goal)
            {
                if(next[pre[x]][0] == x)
                {
                    Rotate(x,1);
                }
                else Rotate(x,0);
            }
        }
        if(!goal) root = x;
    }
    void NewNode(int &x,int y,int val)
    {
        x = ++Size;
        num[x] = 1;
        pre[x] = y;
        next[x][0] = next[x][1] = 0;
        key[x] = val;
        next[y][val>key[y]] = x;
    }
    void Insert(int val)//插入节点
    {
        int x,y;
        for(x = root,y = 0;x;x = next[x][val>key[x]])
        {
            y = x;
            num[x]++;
        }
        NewNode(x,y,val);
        Splay(x,0);
    }
    int Search(int val) //查询比小于等于val的节点的位置
    {
        int res,x;
        for(res = 0, x = root;x;x = next[x][val>key[x]])
        {
            if(key[x] >= val && key[res] >= key[x])
            {
                res = x;
            }
        }
        return res;
    }
    int Select(int k)//查找第k大。
    {
        int x  = root;
        k = num[root]-k;
        for(x = root; num[next[x][0]]+1!=k;)
        {
            if(num[next[x][0]]+1<k)
            {
                k -= num[next[x][0]]+1;
                x = next[x][1];
            }
            else x = next[x][0];
        }
        Splay(x,0);

        return key[x];
    }
    void Init()
    {
        root = Size = 0;
        num[0] = next[0][0] = next[0][1] = pre[0] ;
        key[0] = INF;
        Insert(INF);
    }
}Tr;

int main()
{
    int q,Mi,diff,ans,data;
    char op[2];
    while(~scanf("%d %d",&q,&Mi))
    {
        Tr.Init();
        diff = ans = 0;
        while(q--)
        {
            scanf("%s %d",op,&data);
            if(op[0] == ‘I‘)
            {
                if(data >= Mi)
                {
                    Tr.Insert(data-Mi+diff);
                }
            }
            else if(op[0] == ‘A‘)
            {
                diff-=data;
            }
            else if(op[0] == ‘S‘)
            {
                diff += data;
                Tr.Splay(Tr.Search(diff),0);
                ans+=Tr.num[Tr.next[Tr.root][0]];
                Tr.num[Tr.root] -= Tr.num[Tr.next[Tr.root][0]];
                Tr.next[Tr.root][0] = 0;
            }
            else
            {
                if(data>=Tr.num[Tr.root])
                {
                    printf("-1\n");
                }
                else
                {
                    printf("%d\n",Tr.Select(data)+Mi-diff);
                }
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}