SPOJ3273 Order statistic set treap模板

题目链接：http://www.spoj.com/problems/ORDERSET/

题意：给你四个操作，将x插入节点，将值为x的节点删除，找第K大的节点，找值为X的节点是第几大

解题思路：treap树性质，copy了 clj 在 nocow 上的模板，利用 指针引用，孩子数组来简化代码

解题代码：

// File Name: treap.cpp
// Author: darkdream
// Created Time: 2014年07月22日 星期二 09时06分23秒

#include<vector>
#include<list>
#include<map>
#include<set>
#include<deque>
#include<stack>
#include<bitset>
#include<algorithm>
#include<functional>
#include<numeric>
#include<utility>
#include<sstream>
#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<ctime>
using namespace std;

const int inf = ~0U>>1;
class treap
{
   struct node{
     int value , key ,size;
     node(int v, node *n):value(v)
     {c[0] = c[1]= n; size = 1; key = rand()-1;}
     void rz(){size =c[0]->size + c[1]->size+1;}
     node*c[2];
   }*root,*null;
   void rot(node *&t,bool d)
   {
       node *c = t->c[d];
       t->c[d] = c->c[!d];
       c->c[!d] = t; 
       t->rz();c->rz();
       t = c;
   }
   void insert(node *&t,int x)
   {
       if(t == null)
       {
         t = new node(x,null);
         return ; 
       }
       if(x == t->value) return;
       bool d = x > t->value;
       insert(t->c[d],x);
       if(t->c[d]->key < t->key) //把小的随机值移动到上面
          rot(t,d);
       else t->rz();
   }
   void Delete(node *&t,int x)
   {
      if(t == null) return;
      if(t->value == x)  //將这个值一直旋转到叶子节点然后删除
      {
          bool d = t->c[1]->key < t->c[0]->key;
          if(t->c[d] == null)
          {
              delete t;
              t = null;
              return ;
          }
          rot(t,d);
          Delete(t->c[!d],x);
      }
      else{
        bool d = x>t->value;
        Delete(t->c[d],x);
      }
      t->rz();
   }
   int select(node *t ,int k )
   {
      int r = t->c[0]->size;
      if(k ==  r)
         return t->value;
      if(k < r) return select(t->c[0],k);
      return select(t->c[1], k - r - 1);
   }
   int rank(node *t , int x)
   {
       if(t == null) return 0 ; 
       int r = t->c[0]->size;
       if(x == t->value)
           return r;
       if(x < t->value)  return rank(t->c[0],x);
       return r+1+rank(t->c[1],x);
   }
   public:
      treap()
      {
        null = new node(0,0);
        null ->size = 0 ;
        null ->key = inf;
        root = null;
      }
      void ins(int x)
      {
        insert(root,x);
      }
      int sel(int k)
      {
        if(k > root->size) return -inf;
        return select(root,k-1);
      }
      int ran(int x)
      {
        return rank(root,x);
      }
      void del(int x)
      {
         Delete(root,x);
      }
}T;
int main(){
    //printf("%d
",inf);   
      //freopen("in","r",stdin);
    int m;scanf("%d
",&m);    
    char t;int x,tmp;
    while(m--)
    {
        scanf("%c %d
",&t,&x);
        switch(t)
        {
            case 'I':T.ins(x);break;
            case 'D':T.del(x);break;
            case 'K':tmp=T.sel(x);if(tmp==-inf)printf("invalid
");else printf("%d
",tmp);break;
            case 'C':printf("%d
",T.ran(x));break;
        }        
    }
return 0;
}