AVL tree

AVL tree.cpp

#ifndef AVL_TREE
#define AVL_TREE
template<typename T>
class avl_tree{
	private:
		struct node{
			node *ch[2];
			int size;
			char h;
			T data;
			inline void up(){h=ch[ch[0]->h<ch[1]->h]->h+1;}
			node(const T&d):size(1),h(1),data(d){}
			node():size(0),h(0){ch[0]=ch[1]=this;}
		}*nil,*root;
		inline void rotate(node *&a,bool d){
			node *b=a;
			a=a->ch[!d];
			b->ch[!d]=a->ch[d];
			a->ch[d]=b;
			a->size=b->size;
			b->size=b->ch[0]->size+b->ch[1]->size+1;
			b->up(),a->up();
		}
		inline void balanced(node *&o,bool d){
			if(o->ch[d]->h-o->ch[!d]->h>1){
				node *&t=o->ch[d];
				if(t->ch[d]->h>t->ch[!d]->h)rotate(o,!d);
				else rotate(o->ch[d],d),rotate(o,!d);
			}else o->up();
		}
		void insert(node *&o,const T &data){
			if(!o->size){
				o=new node(data);
				o->ch[0]=o->ch[1]=nil;
			}else{
				o->size++;
				bool d=o->data<data;
				insert(o->ch[d],data);
				balanced(o,d);
			}
		}
		bool erase(node *&o,const T &data){
			if(!o->size)return 0;
			if(o->data==data){
				if(!o->ch[0]->size||!o->ch[1]->size){
					node *t=o;
					o=o->ch[0]->size?o->ch[0]:o->ch[1];
					delete t;
				}else{
					o->size--;
					node *tmd=o->ch[1];
					while(tmd->ch[0]->size)tmd=tmd->ch[0];
					o->data=tmd->data;
					erase(o->ch[1],tmd->data);
					balanced(o,0);
				}return 1;
			}
			bool d=o->data<data;
			if(erase(o->ch[d],data)){
				o->size--,balanced(o,!d);
				return 1;
			}else return 0;
		}
		void clear(node *&o){
			if(o->size)clear(o->ch[0]),clear(o->ch[1]),delete(o);
		}
	public:
		avl_tree():nil(new node),root(nil){}
		~avl_tree(){clear(root),delete nil;}
		inline void clear(){clear(root),root=nil;}
		inline void insert(const T &data){
			insert(root,data);
		}
		inline bool erase(const T &data){
			return erase(root,data);
		}
		inline bool find(const T&data){
			node *o=root;
			while(o->size&&o->data!=data)o=o->ch[o->data<data];
			return o->size;
		}
		inline int rank(const T&data){
			int cnt=0;
			for(node *o=root;o->size;)
			if(o->data<data)cnt+=o->ch[0]->size+1,o=o->ch[1];
			else o=o->ch[0];
			return cnt;
		}
		inline const T&kth(int k){
			for(node *o=root;;)
			if(k<=o->ch[0]->size)o=o->ch[0];
			else if(k==o->ch[0]->size+1)return o->data;
			else k-=o->ch[0]->size+1,o=o->ch[1];
		}
		inline const T&operator[](int k){
			return kth(k);
		}
		inline const T&preorder(const T&data){
			node *x=root,*y=0;
			while(x->size)
			if(x->data<data)y=x,x=x->ch[1];
			else x=x->ch[0];
			if(y)return y->data;
			return data;
		}
		inline const T&successor(const T&data){
			node *x=root,*y=0;
			while(x->size)
			if(data<x->data)y=x,x=x->ch[0];
			else x=x->ch[1];
			if(y)return y->data;
			return data;
		}
		inline int size(){return root->size;}
		inline int height(){return root->h;}
};
#endif