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Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors. OJ's undirected graph serialization: Nodes are labeled 阅读全文
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A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy 阅读全文
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Given n points in the plane that are all pairwise distinct, a "boomerang" is a tuple of points (i, j, k) such that the distance between iand j equals 阅读全文
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Given n points on a 2D plane, find if there is such a line parallel to y-axis that reflect the given points. Example 1: Given points = [[1,1],[-1,1]], 阅读全文
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Given n points on a 2D plane, find the maximum number of points that lie on the same straight line. 本题是比较难的题目，首先需要弄懂一点，就是最大公约数是最大的可整除数，也就是默认为k值（y=kx+b 阅读全文
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Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n. For example, given n = 12, 阅读全文