随笔分类 - LeetCode
摘要：Design and implement a data structure for Least Frequently Used (LFU) cache. It should support the following operations: get and put. get(key) - Get t
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摘要：Given an array of strings words (without duplicates), return all the concatenated words in the given list of words. A concatenated word is defined as
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摘要：Remember the story of Little Match Girl? By now, you know exactly what matchsticks the little match girl has, please find out a way you can make one s
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摘要：Given a string, sort it in decreasing order based on the frequency of characters. Example 1: Input: "tree" Output: "eert" Explanation: 'e' appears twi
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摘要：Given a root node reference of a BST and a key, delete the node with the given key in the BST. Return the root node reference (possibly updated) of th
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摘要：Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or
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摘要：Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements of [1, n]
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摘要：You are given two linked lists representing two non-negative numbers. The most significant digit comes first and each of their nodes contain a single
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摘要：Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements that appear twi
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摘要：The Hamming distance between two integers is the number of positions at which the corresponding bits are different. Now your job is to find the total
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摘要：The Hamming distance between two integers is the number of positions at which the corresponding bits are different. Given two integers x and y, calcul
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摘要：Given a non-empty string, encode the string such that its encoded length is the shortest. The encoding rule is: k[encoded_string], where the encoded_s
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摘要：In the computer world, use restricted resource you have to generate maximum benefit is what we always want to pursue. For now, suppose you are a domin
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摘要：In this problem, your job to write a function to check whether a input string is a valid IPv4 address or IPv6 address or neither. IPv4 addresses are c
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摘要：Winter is coming! Your first job during the contest is to design a standard heater with fixed warm radius to warm all the houses. Now, you are given p
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摘要：Define S = [s,n] as the string S which consists of n connected strings s. For example, ["abc", 3] ="abcabcabc". On the other hand, we define that stri
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摘要：Given a list of points that form a polygon when joined sequentially, find if this polygon is convex (Convex polygon definition). Note: Example 1: Exam
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摘要：Consider the string s to be the infinite wraparound string of "abcdefghijklmnopqrstuvwxyz", so s will look like this: "...zabcdefghijklmnopqrstuvwxyza
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摘要：Count the number of segments in a string, where a segment is defined to be a contiguous sequence of non-space characters. Please note that the string
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摘要：A group of friends went on holiday and sometimes lent each other money. For example, Alice paid for Bill's lunch for $10. Then later Chris gave Alice
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