随笔分类 - Hash Table
摘要：Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already presen
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摘要：Design a simplified version of Twitter where users can post tweets, follow/unfollow another user and is able to see the 10 most recent tweets in the u
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摘要：Given a non-empty array of integers, return the k most frequent elements. Example 1: Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] Example 2: Input
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摘要：Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the arr
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摘要：Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the
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摘要：Given a non-empty array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runti
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摘要：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
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摘要：Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive intege
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摘要：Given a pattern and a string str, find if str follows the same pattern. Here follow means a full match, such that there is a bijection between a lette
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摘要：Given n points on a 2D plane, find the maximum number of points that lie on the same straight line. Example 1: Example 2: my code: can't determine the
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摘要：Count the number of prime numbers less than a non-negative number, n. Example: Approach #1: C++. Approach #2: Java. Approach #3: Python.
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摘要：Given a list of unique words, find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] +
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摘要：You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time
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摘要：Given two strings s and t, determine if they are isomorphic. Two strings are isomorphic if the characters in s can be replaced to get t. All occurrenc
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摘要：All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: "ACGAATTCCG". When studying DNA, it is sometimes useful to
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摘要：Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If the fractional part is repeating
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摘要：Given a binary tree, return the inorder traversal of its nodes' values. Example: Follow up: Recursive solution is trivial, could you do it iteratively
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摘要：Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make pro
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