摘要：
Implement a basic calculator to evaluate a simple expression string.The expression string may contain open(and closing parentheses), the plus+or minus... 阅读全文
摘要：
Given a binary tree, return thepreordertraversal of its nodes' values.For example:Given binary tree{1,#,2,3} 1 \ 2 / 3return[1,2,3].前序遍历二叉... 阅读全文
摘要：
Given a sorted integer array without duplicates, return the summary of its ranges.For example, given[0,1,2,4,5,7], return["0->2","4->5","7"].就是概括区间的方式... 阅读全文
摘要：
Given a set of distinct integers,nums, return all possible subsets.Note:Elements in a subset must be in non-descending order.The solution set must not... 阅读全文