摘要：
Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Example: 1 struct cmp { 2 bool operator () (ListNod 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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Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. Example: 阅读全文
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Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: No 阅读全文
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Given a linked list, remove the n-th node from the end of list and return its head. Example: Note: Given n will always be valid. Follow up: Could you 阅读全文
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Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique q 阅读全文