随笔分类 - LeetCode
摘要：Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Examples: Note: You may assume the
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摘要：Given an integer n, return 1 - n in lexicographical order. For example, given 13, return: [1,10,11,12,13,2,3,4,5,6,7,8,9]. Please optimize your algori
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摘要：Shuffle a set of numbers without duplicates. Example: 这道题让我们给数组洗牌，也就是随机打乱顺序，那么由于之前那道题Linked List Random Node我们接触到了水塘抽样Reservoir Sampling的思想，这道题实际上这道题也
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摘要：Given a nested list of integers represented as a string, implement a parser to deserialize it. Each element is either an integer, or a list -- whose e
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摘要：Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the rans
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摘要：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. Implement the
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摘要：Design a data structure that supports all following operations in average O(1) time. Note: Duplicate elements are allowed. insert(val): Inserts an ite
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摘要：Design a data structure that supports all following operations in average O(1) time. Example: 这道题让我们在常数时间范围内实现插入删除和获得随机数操作，如果这道题没有常数时间的限制，那么将会是一道非常简单的
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摘要：Design a Phone Directory which supports the following operations: Example: 又是一道设计题，让我们设计一个电话目录管理系统，可以分配电话号码，查询某一个号码是否已经被使用，释放一个号码。既然要分配号码，肯定需要一个数组 num
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摘要：Given an n x n matrix where each of the rows and columns is sorted in ascending order, return the kth smallest element in the matrix. Note that it is
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摘要：Given an array of distinct integers nums and a target integer target, return the number of possible combinations that add up to target. The answer is
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摘要：A sequence of numbers is called a wiggle sequence if the differences between successive numbers strictly alternate between positive and negative. The
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摘要：We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you guess wron
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摘要：We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you guess wron
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摘要：You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k. Define a pair (u, v) which consists of one element from t
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摘要：Your task is to calculate ab mod 1337 where a is a positive integer and b is an extremely large positive integer given in the form of an array. Exampl
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摘要：Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -. Example 1: Input: a = 1, b = 2 Output: 3 Example 2: In
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摘要：You are given two jugs with capacities jug1Capacity and jug2Capacity liters. There is an infinite amount of water supply available. Determine whether
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摘要：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
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摘要：Given a non-negative integer represented as non-empty a singly linked list of digits, plus one to the integer. You may assume the integer do not conta
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