摘要： 题目如下： Given an integer array arr and an integer k, modify the array by repeating it k times. For example, if arr = [1, 2] and k = 3 then the modified 阅读全文

摘要： 题目如下： Given a string s that consists of lower case English letters and brackets. Reverse the strings in each pair of matching parentheses, starting fr 阅读全文

摘要： 题目如下： Given a string text, you want to use the characters of text to form as many instances of the word "balloon" as possible. You can use each charac 阅读全文