Java | Leetcode Java题解之第173题二叉搜索树迭代器

题目：

题解：

class BSTIterator {private TreeNode cur;private Deque<TreeNode> stack;public BSTIterator(TreeNode root) {cur = root;stack = new LinkedList<TreeNode>();}public int next() {while (cur != null) {stack.push(cur);cur = cur.left;}cur = stack.pop();int ret = cur.val;cur = cur.right;return ret;}public boolean hasNext() {return cur != null || !stack.isEmpty();}
}