平衡树肯定无锅，毕竟刚刚A了板子就将std复制了一下

求助！

#include<cstdio>
#include<string>
#include<iostream>
using namespace std;
const int MAXN=100010;
int n,root,a[MAXN],tot,m;
struct Splay_Tree
{
	int father,ch[2],key,cnt,siz;
};
Splay_Tree tree[MAXN];
int lc(int p){return tree[p].ch[0];}
int rc(int p){return tree[p].ch[1];}
void update(int x)
{
	if(x)
	{
		tree[x].siz=tree[x].cnt;
		if(lc(x)) tree[x].siz+=tree[lc(x)].siz;
		if(rc(x)) tree[x].siz+=tree[rc(x)].siz;
	}
	return;
}
void rotate(int x)
{
	int father=tree[x].father;
	int grandfather=tree[father].father;
	int k=rc(father)==x;
	tree[father].ch[k]=tree[x].ch[k^1];
	tree[tree[x].ch[k^1]].father=father;
	tree[x].ch[k^1]=father;
	tree[father].father=x;
	if(grandfather) tree[grandfather].ch[rc(grandfather)==father]=x;
	tree[x].father=grandfather;
	update(father),update(x);
	return;
}
void splay(int x)
{
	int father=tree[x].father;
	int grandfather=tree[father].father;
	while(father)
	{
		if(grandfather)
		{
			if((rc(grandfather)==father)^(rc(father)==x)) rotate(x);
			else rotate(father);
		}
		rotate(x);
		father=tree[x].father;
		grandfather=tree[father].father;
	}
	root=x;
	return;
} 
void insert(int x)
{
	if(!root)
	{
		root=++tot;
		tree[root].father=tree[root].ch[0]=tree[root].ch[1]=0;
		tree[root].siz=tree[root].cnt=1;
		tree[root].key=x;
		return;
	}
	int now=root,lst=0;
	while(true)
	{
		if(tree[now].key==x)
		{
			tree[now].cnt++;
			update(now);
			update(lst);
			splay(now);
			return;
		}
		lst=now;
		now=tree[lst].ch[x>tree[lst].key];
		if(!now)
		{
			tot++;
			tree[lst].ch[x>tree[lst].key]=tot;
			tree[tot].father=lst;tree[tot].ch[0]=tree[tot].ch[1]=0;
			tree[tot].key=x;
			tree[tot].cnt=tree[tot].siz=1;
			update(lst);
			splay(tot);
			return;
		}	
	}
}
int find(int x)
{
	int ans=1,now=root;
	while(now)
	{
		if(x<tree[now].key) now=lc(now);
		else
		{
			if(lc(now)) ans+=tree[lc(now)].siz;
			if(x==tree[now].key)
			{
				splay(now);
				return ans;
			}
			ans+=tree[now].cnt;
			now=rc(now);
		}
	}
	return ans;
}
int find_kth(int x)
{
	int now=root;
	while(true)
	{
		if(lc(now)&&x<=tree[lc(now)].siz) now=lc(now);
		else
		{
			if(lc(now)) x-=tree[lc(now)].siz;
			if(x<=tree[now].cnt)
			{
				splay(now);
				return now;
			}
			x-=tree[now].cnt;
			now=rc(now);
		}
	}
	return false;
}
int pre()
{
	int now=lc(root);
	while(rc(now)) now=rc(now);
	return now;
}
int nxt()
{
	int now=rc(root);
	while(lc(now)) now=lc(now);
	return now;
}
void del(int x)
{
	find(x);
	if(tree[root].cnt>1)
	{
		tree[root].cnt--;
		return;
	}
	if(!lc(root)&&!rc(root))
	{
		root=0;
		return;
	}
	if(!lc(root))
	{
		root=rc(root);
		tree[root].father=0;
		return;
	}
	if(!rc(root))
	{
		root=lc(root);
		tree[root].father=0;
		return;
	}
	int last_root=root;
	splay(pre());
	tree[root].ch[1]=rc(last_root);
	tree[rc(last_root)].father=root;
	update(root);
	return;
}
int main()
{
	scanf("%d",&n);
	for(register int i=1,x;i<=n;i++)
	{
		scanf("%d",&x);
		insert(x);
	}
	scanf("%d",&m);
	for(register int i=1;i<=m;i++)
	{
		char opt[5];
		scanf("%s",opt);
		if(opt[0]=='m') 
		{
			if(n%2==1) printf("%d\n",find_kth(n/2+1));
			else printf("%d\n",find_kth(n>>1));
		}
		else 
		{
			int x;
			scanf("%d",&x);
			insert(x);
			n++;
		}
	}
	return 0;
}
/**
*　　┏┓　　　┏┓+ +
*　┏┛┻━━━┛┻┓ + +
*　┃　　　　　　　┃
*　┃　　　━　　　┃ ++ + + +
*  ████━████+
*  ◥██◤　◥██◤ +
*　┃　　　┻　　　┃
*　┃　　　　　　　┃ + +
*　┗━┓　　　┏━┛
*　　　┃　　　┃ + + + +Code is far away from 　
*　　　┃　　　┃ + bug with the animal protecting 
*　　　┃　 　 ┗━━━┓ 神兽保佑,代码无bug
*　　　┃ 　　　　　　 ┣┓ 
*　　  ┃ 　　　　　 　┏┛
*　    ┗┓┓┏━┳┓┏┛ + + + +
*　　　　┃┫┫　┃┫┫
*　　　　┗┻┛　┗┻┛+ + + +
*/