摘要:
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:"((... 阅读全文
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Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.The brackets must close in the c... 阅读全文
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Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array whic... 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 telephon... 阅读全文
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Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers.... 阅读全文
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Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of ... 阅读全文
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Write a function to find the longest common prefix string amongst an array of strings.这题是寻找一组字符串的最长公共前缀,举个例子:“abc” "a"显然lPrefixString = "a",注意检查空串的情况!... 阅读全文