【Hihocder 1329】——Splay

伸展树的插入，区间删除，区间查询,自己手残，debug了半天

#include <bits/stdc++.h>

using namespace std;

const int INF = 0x3f3f3f3f;

typedef struct node
{
int data;

node *Left,*Right,*fa;

}Node;

void Zig(Node *p)
{
Node *C = p->Left;

Node *s = C->Right;

Node *fa = p->fa;

if(fa)
{
if(fa->Left == p) fa->Left = C;
else fa->Right = C;
}

C->fa = fa;

C->Right = p;

p->fa = C;

p->Left = s;

if(s) s->fa = p;
}

void Zag(Node *p)
{
Node *c = p->Right;

Node *s = c->Left ;

Node *fa = p->fa;

if(fa)
{
if(fa->Left == p) fa->Left = c;
else fa->Right = c;
}

c->fa = fa;

p->Right = s;

if(s) s->fa = p;

c->Left = p;

p->fa = c;
}

Node * Insert(Node *&p,int value,Node *fa)
{
if(!p)
{
p = new Node;
p->Left = p->Right = NULL;
p->fa = fa;
p->data = value;
return p;
}

if(p->data == value) return p;
if(p->data < value) return Insert(p->Right,value,p);
else return Insert(p->Left,value,p);
}

void Rotate(Node *p,Node *fa)
{
while(p->fa != fa)
{
Node *f = p->fa;
Node *Gf = f->fa;
if(Gf != fa)
{
if(Gf->Left == f)
{
if(f->Left == p)
{
Zig(Gf);
Zig(f);
}
else
{
Zag(f);
Zig(Gf);
}
}
else
{
if(f->Left == p)
{
Zig(f);
Zag(Gf);
}
else
{
Zag(Gf);
Zag(f);
}
}
}
else
{
if(f->Left == p) Zig(f);
else Zag(f);
}
}
}

Node *ans;

void Min(Node *p,int value)
{
if(!p) return ;

if(p->data == value)
{
ans = p;

return ;
}

if(p->data < value)
{
ans = p;

Min(p->Right,value);
}

else Min(p->Left,value);
}

void Max(Node *p,int value)
{
if(!p) return ;

if(p->data == value)
{
ans = p;

return ;

}

if(p->data>value)
{
ans = p;

Max(p->Left,value);
}

else Max(p->Right,value);
}

int main()
{
int n;

char op[3];

int l,r;

Node *root = NULL;

scanf("%d",&n);

Insert(root,-INF,NULL);

Insert(root,INF,NULL);

while(n--)
{
scanf("%s",op);

if(op[0] == 'I')
{
scanf("%d",&l);

Node * p = Insert(root,l,NULL);

Rotate(p,NULL);

root = p;

}
else if(op[0] == 'Q')
{
scanf("%d",&l);

ans = NULL;

Min(root,l);

Rotate(ans,NULL);

root = ans;

printf("%d\n",ans->data);
}
else if(op[0] == 'D')
{
scanf("%d %d",&l,&r);

ans = NULL; Min(root,l-1);

Rotate(ans,NULL);

root = ans;

ans = NULL;

Max(root,r+1);

Rotate(ans,root);

root->Right->Left = NULL;
}
}
return 0;
}