#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<queue>
#include<math.h>
#include<iostream>
#include<algorithm>
using namespace std;
typedef struct node
{
int data;
int d;
struct node *l,*r;
}tree;
int deep(tree*root)
{
if(!root)
return -1;
else
return root->d;
}
tree* LL(tree*root)//左左情况进行右旋
{
tree*p = root->l;
root->l = p->r;
p->r = root;
p->d =max(deep(p->l),deep(p->r))+1;
root->d = max(deep(root->l),deep(root->r))+1;
return p;
}
tree* RR(tree*root)
{
tree*p = root->r;
root->r = p-> l;
p->l = root;
p->d =max(deep(p->l),deep(p->r))+1;
root->d = max(deep(root->l),deep(root->r))+1;
return p;
}
tree* LR(tree*root)//左右情况先进行左旋（右右），然后左旋（左左）
{
root->l = RR(root->l);
return LL(root);
}
tree* RL(tree*root)
{
root->r = LL(root->r);
return RR(root);
}
tree* creat(tree*root,int x)
{
if(root==NULL)
{
root = (tree*)malloc(sizeof(tree));
root->d = 0;
root->data = x;
root->l = root->r = NULL;
}
else if(root->data>x)
{
root->l = creat(root->l,x);
if(deep(root->l)-deep(root->r)>1)
{
if(root->l->data>x)
{
root = LL(root);
}
else
{
root = LR(root);
}
}
}
else if(root->data<=x)
{
root->r = creat(root->r,x);
if(deep(root->r)-deep(root->l)>1)
{
if(root->r->data>x)
{
root = RL(root);
}
else
root = RR(root);
}
}
root->d = max(deep(root->l),deep(root->r))+1;//及时更新每个节点的深度
return root;
}
int main()
{
int n,i,x;
scanf("%d",&n);
tree*root = NULL;
for(i = 0;i < n;i++)
{
scanf("%d",&x);
root = creat(root,x);
}
printf("%d\n",root->data);
return 0;
}
/***************************************************
User name: jk160505徐红博
Result: Accepted
Take time: 0ms
Take Memory: 152KB
Submit time: 2017-02-08 15:25:50
****************************************************/
