摘要： Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tree [3 阅读全文

摘要： Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Note:A solution using O(n) space i 阅读全文

摘要： Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is symmet 阅读全文

摘要： Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical a 阅读全文

摘要： Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only 阅读全文

摘要： Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example,Given:s1 = "aabcc",s2 = "dbbca", When s3 = "aadbbcbcac", ret 阅读全文