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题目描述： Given a singly linked list, determine if it is a palindrome. Follow up:Could you do it in O(n) time and O(1) space? 解题思路： 使用O(n)的时间复杂度及O(1)的时间复杂 阅读全文
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题目描述： Given a binary tree, return all root-to-leaf paths. For example, given the following binary tree: 1 / \ 2 3 \ 5 All root-to-leaf paths are: ["1- 阅读全文
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题目描述: Remove all elements from a linked list of integers that have value val. ExampleGiven: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6Return: 1 -- 阅读全文
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题目描述： Given a pattern and a string str, find if str follows the same pattern. Here follow means a full match, such that there is a bijection between a 阅读全文
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题目描述： You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Eac 阅读全文
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题目描述： Given two strings s and t, determine if they are isomorphic. Two strings are isomorphic if the characters in s can be replaced to get t. All occ 阅读全文