28 Jul 2017
问题描述： Remove all elements from a linked list of integers that have value val. Example Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6 Return: 1 --> 2 --> 3 --> 4 -->…

16 Jul 2017
问题描述： We define the Perfect Number is a positive integer that is equal to the sum of all its positive divisors except itself. Now, given an integer n, write a function that returns true when it is a perfect number and false when it is not. Example: Input: 28 Output:…

16 Jul 2017
问题描述： Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. For example: Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1 return…

15 Jul 2017
Welcome to StackEdit! Hey! I'm your first Markdown document in StackEdit[1]. Don't delete me, I'm very helpful! I can be recovered anyway in the Utils tab of the Settings dialog. Documents StackEdit stores your documents in your browser, which means all your documents are automatically saved locally and are…

28 Jun 2017
【题目】 You need to construct a string consists of parenthesis and integers from a binary tree with the preorder traversing way. The null node needs to be represented by empty parenthesis pair "()". And you need to omit all the empty parenthesis pairs that don't affect the one-to-one mapping…