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Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. Example "A man, a plan, a canal: Panama" 阅读全文
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Description Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those l 阅读全文
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Given an m x n matrix of non-negative integers representing the height of each unit cell in a continent, the "Pacific ocean" touches the left and top 阅读全文
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Given a 01 matrix M, find the longest line of consecutive one in the matrix. The line could be horizontal, vertical, diagonal or anti-diagonal. Exampl 阅读全文
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I: Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5,Return II: Given an index k, return the kth row of t 阅读全文
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Given a string and a string dictionary, find the longest string in the dictionary that can be formed by deleting some characters of the given string. 阅读全文
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Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example,Given [100, 4, 200, 1, 3, 2],The longes 阅读全文
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Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: 1 阅读全文
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Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telepho 阅读全文
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Given a string containing only three types of characters: '(', ')' and '*', write a function to check whether this string is valid. We define the vali 阅读全文