摘要： Given a string, sort it in decreasing order based on the frequency of characters. Example 1: Example 2: Example 3: 这题主要是考对数据结构的应用。首先需要用HashMap对字符进行出现次 阅读全文

摘要： Suppose you have a random list of people standing in a queue. Each person is described by a pair of integers (h, k), where h is the height of the pers 阅读全文