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Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacen 阅读全文
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Given a nested list of integers, return the sum of all integers in the list weighted by their depth. Each element is either an integer, or a list -- w 阅读全文
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There are n bulbs that are initially off. You first turn on all the bulbs. Then, you turn off every second bulb. On the third round, you toggle every 阅读全文
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Design a hit counter which counts the number of hits received in the past 5 minutes. Each function accepts a timestamp parameter (in seconds granulari 阅读全文
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Given a non-negative number represented as a singly linked list of digits, plus one to the number. The digits are stored such that the most significan 阅读全文
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Assume you have an array of length n initialized with all 0's and are given k update operations. Each operation is represented as a triplet: [startInd 阅读全文
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Given a binary tree, collect a tree's nodes as if you were doing this: Collect and remove all leaves, repeat until the tree is empty. Example:Given bi 阅读全文
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Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and r 阅读全文