摘要： 题目描述： Implement the following operations of a stack using queues. push(x) -- Push element x onto stack. pop() -- Removes the element on top of the sta 阅读全文

摘要： 题目描述： 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 阅读全文

摘要： 题目描述： Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3,Return [1,3,3,1]. 解题思路： 每次在上一个list前面插入1，然后后面的每两个间相加赋值给前一 阅读全文