摘要：
Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. A mapping of digit to le 阅读全文
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Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the thr 阅读全文
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Given an array nums of n integers, are there elements a, b, c in nums such that a+ b + c = 0? Find all unique triplets in the array which gives the su 阅读全文
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Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty string "". Exampl 阅读全文
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Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. For example, two is written as II in Roman numeral, just two one's 阅读全文
摘要：
Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. For example, two is written as II in Roman numeral, just two one's 阅读全文