[LOG] Size Balanced Tree

一个SBT模板。(平衡BST)
据说插入效率比红黑树还高= =
其中Maintain函数的效率可以进一步改进
(话说也就一个Maintain能优化其它的都跟标准BST一毛一样= =)
想用的话直接拷贝过去用把= =
API都很清楚把= =

//KeyType must be comparable!!!!!!!//overload both operator '>' and '<'//or you will get a compilation errortemplate<typename KeyType,typename ValType>class Size_Balanced_Tree {    struct node {        int Size;//important!!!                 //cnt the number of child nodes        KeyType key;        ValType val;        node *lchild, *rchild;        node(KeyType k, ValType v) {            lchild = 0, rchild = 0; Size = 0;            val = v; key = k;        }    };    node *root;    inline int SizeOf(node *&target) {        return target ? target->Size : 0;    }    void Lrotate(node *&target) {        node *temp = target->lchild;        target->lchild = temp->rchild;        temp->rchild = target;        temp->Size = target->Size;        target->Size = SizeOf(target->lchild) + SizeOf(target->rchild) + 1;        target = temp;    }    void Rrotate(node *&target) {        node *temp = target->rchild;        target->rchild = temp->lchild;        temp->lchild = target;        temp->Size = target->Size;        target->Size = SizeOf(target->lchild) + SizeOf(target->rchild) + 1;        target = temp;    }    void Maintain(node *& target) {        if (target->lchild != NULL) {            if (SizeOf(target->rchild) < SizeOf(target->lchild->lchild))                Lrotate(target);            else if (SizeOf(target->rchild) < SizeOf(target->lchild->rchild)) {                Rrotate(target->lchild);                Lrotate(target);            }Maintain(target->lchild);        }        if (target->rchild != NULL) {            if (SizeOf(target->lchild) < SizeOf(target->rchild->rchild))                Rrotate(target);            else if (SizeOf(target->lchild) < SizeOf(target->rchild->lchild)) {                Lrotate(target->rchild);                Rrotate(target);            }Maintain(target->rchild);        }        return;    }    void insert(node *&target, KeyType &key, ValType &val) {        if (!target) {            target = new node(key, val);            return;        }        target->Size++;        if (key > target->key)insert(target->rchild, key, val);        else if (key != target->key)insert(target->lchild, key, val);        else return;        Maintain(target);    }    ValType query(node *&target, KeyType key) {        if (target == NULL)            return 0;        if (target->key == key)return target->val;        else if (target->key < key)return query(target->rchild, key);        else return query(target->lchild, key);    }public:    Size_Balanced_Tree() {        root = 0;    }//returns the value of the node with the max key in the whole tree    ValType max() {        node *scout = root;        while (scout->rchild != NULL)            scout = scout->rchild;        return scout->val;    }//= =    ValType min() {        node *scout = root;        while (scout->lchild != NULL)            scout = scout->lchild;        return scount->val;    }//returns the rank(from min) of the key in the tree    int rank(KeyType key) {        node *scout = root;        int r = 0;        while (scout->key != key) {            if (scout->key < key) {                r += scout->lchild->Size + 1;                scout = scout->rchild;            }            else if (scout->key > key)scout = scout->lchild;        }        r += scout->lchild->Size + 1;        return r;    }//anything not clear= =?    void insert(KeyType key, ValType val) {        insert(root, key, val);    }    ValType query(KeyType key) {        return query(root, key);    }};