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Implement a trie with insert, search, and startsWith methods. Note:You may assume that all inputs are consist of lowercase letters a-z. 解法： Trie（字典树）的 阅读全文
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Given an integer matrix, find the length of the longest increasing path. From each cell, you can either move to four directions: left, right, up or do 阅读全文
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Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: Wh 阅读全文
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Given an array of integers with possible duplicates, randomly output the index of a given target number. You can assume that the given target number m 阅读全文
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水塘抽样是一系列的随机算法，其目的在于从包含n个项目的集合S中选取k个样本，其中n为一很大或未知的数量，尤其适用于不能把所有n个项目都存放到主内存的情况。 在高德纳的计算机程序设计艺术中，有如下问题：可否在一未知大小的集合中，随机取出一元素？。或者是Google面试题： I have a linke 阅读全文
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Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possib 阅读全文
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You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices of substring(s) in s that is a conca 阅读全文