「模板」 左偏树

template<typename T, typename _Compare=std::less<T> >class leftist_tree {private:    struct node {        T data;        int deep;        node *l, *r;        node(const T &d) : data(d), deep(1), l(0), r(0) {}    } *root;    int _size;    _Compare cmp;    inline int deep(node *o) { return o ? o->deep : 0; }    node *Merge(node *a, node *b) {        if (!a || !b)return a ? a : b;        if (cmp(a->data, b->data)) {            std::swap(a,b);        }        a->r = Merge(a->r, b);        if (deep(a->l) < deep(a->r)) {            std::swap(a->l, a->r);        }        a->deep = deep(a->l) + 1;        return a;    }    void _clear(node *&o) {        if (o)_clear(o->l), _clear(o->r), delete o;    }public:    leftist_tree() : root(0), _size(0) {}    ~leftist_tree() { _clear(root); }    inline void clear() {        _clear(root);        root = 0;        _size = 0;    }    inline void merge(leftist_tree &o) {        root = Merge(root, o.root);        o.root = 0;        _size += o._size;        o._size = 0;    }    inline void swap(leftist_tree &o) {        node *t = root;        root = o.root;        o.root = t;        int st = _size;        _size = o._size;        o._size = st;    }    inline void push(const T &data) {        _size++;        root = Merge(root, new node(data));    }    inline void pop() {        if (_size)_size--;        node *tmd = Merge(root->l, root->r);        delete root;        root = tmd;    }    inline const T &top() { return root->data; }    inline int size() { return _size; }    inline bool empty() { return !_size; }};