摘要：
Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \3 4 4 3But the following is not: 1 / \ 2 2 \ \ 3 3Note:Bonus points if you could solve it both recursively and iterati... 阅读全文
摘要：
Given a binary tree, find its minimum depth.The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.思考：考虑[1,2]这种情况，返回树最低高度为2。所以分两种情况，有一棵子树不在时，返回另一棵子树树高+1，否则返回矮子树高+1./** * Definition for binary tree * struct TreeNode { * int val; * Tre... 阅读全文
摘要：
Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.For example:Given the below binary tree andsum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1return[ [5,4,11,2]... 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 and the nodes have the same value.思考：DFS./** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right... 阅读全文