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Given a non-empty array of integers, return the k most frequent elements. Example 1: Example 2: Input: nums = [1], k = 1 Output: [1] Example 2: Note: 阅读全文
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There are N students in a class. Some of them are friends, while some are not. Their friendship is transitive in nature. For example, if A is a direct 阅读全文
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Given a binary search tree and a node in it, find the in-order successor of that node in the BST. Note: If the given node has no in-order successor in 阅读全文
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Given a binary tree, return the vertical order traversal of its nodes' values. (ie, from top to bottom, column by column). If two nodes are in the sam 阅读全文
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Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that support the peek() operation -- it e 阅读全文
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Given an array nums, there is a sliding window of size k which is moving from the very left of the array to the very right. You can only see the k num 阅读全文
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Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place. Example 1: Example 2: Follow up: A straight forward solu 阅读全文
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According to the Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John 阅读全文
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Suppose you are at a party with n people (labeled from 0 to n - 1) and among them, there may exist one celebrity. The definition of a celebrity is tha 阅读全文
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Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path betwe 阅读全文