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You need to construct a string consists of parenthesis and integers from a binary tree with the preorder traversing way. The null node needs to be rep 阅读全文
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In English, we have a concept called root, which can be followed by some other words to form another longer word - let's call this word successor. For 阅读全文
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In a given integer array nums, there is always exactly one largest element. Find whether the largest element in the array is at least twice as much as 阅读全文
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Given an array of integers A with even length, return true if and only if it is possible to reorder it such that A[2 * i + 1] = 2 * A[2 * i] for every 阅读全文
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Whenever you expose a web service / api endpoint, you need to implement a rate limiter to prevent abuse of the service (DOS attacks). Implement a Rate 阅读全文