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题目描述 Given a linked list, return the node where the cycle begins. If there is no cycle, return null. To represent a cycle in the given linked list, we 阅读全文
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题目描述 Given a string, find the length of the longest substring without repeating characters. Example 1: Input: "abcabcbb" Output: 3 Explanation: The an 阅读全文
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题目描述 144. Binary Tree Preorder Traversal 94. Binary Tree Inorder Traversal 145. Binary Tree Postorder Traversal 前序排列 :根-左-右 中序排列: 左-根-右 后序排列:左-右-根 参考答 阅读全文
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题目描述 Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Examples: Note: You may assum 阅读全文
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题目描述 Suppose Andy and Doris want to choose a restaurant for dinner, and they both have a list of favorite restaurants represented by strings. You need 阅读全文
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题目介绍 Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would ha 阅读全文
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问题描述 Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive i 阅读全文
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题目描述 Given two arrays, write a function to compute their intersection. Example 1: Example 2: Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4] Output: [9,4] 阅读全文
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问题描述 Given an encoded string, return its decoded string. The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets 阅读全文
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问题描述 Given a binary tree, return the inorder traversal of its nodes' values. （左 - 根 - 右） Example: Follow up: Recursive solution is trivial, could you 阅读全文