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Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). You are given a target va 阅读全文
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Given an directed graph, a topological order of the graph nodes is defined as follow: For each directed edge A -> B in graph, A must before B in the o 阅读全文
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The structure of Expression Tree is a binary tree to evaluate certain expressions.All leaves of the Expression Tree have an number string value. All n 阅读全文
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Given two arrays of length m and n with digits 0-9 representing two numbers. Create the maximum number of length k <= m + n from digits of the two. Th 阅读全文
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Given a nested list of integers, implement an iterator to flatten it. Each element is either an integer, or a list -- whose elements may also be integ 阅读全文