摘要：
Given an array of strings, return all groups of strings that are anagrams. Note: All inputs will be in lower-case. 题意：anagrams的意思是回文构词法。回文构词法有一个特点：单词里 阅读全文
摘要：
Given a string s consists of upper/lower-case alphabets and empty space characters' ', return the length of last word in the string. If the last word 阅读全文
摘要：
Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below 阅读全文
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Implement regular expression matching with support for'.'and'*'. 题意：' . '能匹配任意字符，‘ * ‘表示之前的那个字符可以是0个、1个或者多个，（注意：s= ba和 p= a*bc也是匹配的，*表示p中 * 之前的字符为0个,但 阅读全文
摘要：
Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters fo 阅读全文