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Problem Definition:Given a digit string, return all possible letter combinations that the number could represent.A mapping of digit to letters (just l... 阅读全文
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Problem Definition: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 ... 阅读全文
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Problem Definition: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 whic... 阅读全文
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Problem Definition:Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999.Solution: 1）思路基本上就是这个样子，不... 阅读全文