wjx_sky的博客

题目：Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11]

题目： Given a string, your task is to count how many palindromic substrings in this string. The substrings with different start indexes or end indexes are counted as different substrings even they con