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Excel Sheet Column TitleGiven a non-zero positive integer, return its corresponding column title as appear in an Excel sheet.For example: 1 -> A ... 阅读全文
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Letter Combinations of a Phone NumberGiven a digit string, return all possible letter combinations that the number could represent.A mapping of digit ... 阅读全文
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Valid ParenthesesGiven a string containing just the characters'(',')','{','}','['and']', determine if the input string is valid.The brackets must clos... 阅读全文
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Generate ParenthesesGivennpairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, givenn= 3, a sol... 阅读全文
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Merge k Sorted ListsMergeksorted linked lists and return it as one sorted list. Analyze and describe its complexity.多路归并。1、用make_heap函数维护一个大小为k的最小堆。注：... 阅读全文