摘要：
Description: Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string 阅读全文
摘要：
Description: Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty stri 阅读全文
摘要：
Description: Given an array of non-negative integers nums, you are initially positioned at the first index of the array. Each element in the array rep 阅读全文