随笔分类 - LeetCode
摘要：Let's call any (contiguous) subarray B (of A) a mountain if the following properties hold: B.length >= 3 There exists some 0 < i < B.length - 1 such t
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摘要：Given two strings S and T, return if they are equal when both are typed into empty text editors. # means a backspace character. Example 1: Input: S =
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摘要：Given a string S of digits, such as S = "123456579", we can split it into a Fibonacci-like sequence [123, 456, 579]. Formally, a Fibonacci-like sequen
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摘要：Given a binary search tree and a node in it, find the in-order successor of that node in the BST. The successor of a node p is the node with the small
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摘要：There are N rooms and you start in room 0. Each room has a distinct number in 0, 1, 2, ..., N-1, and each room may have some keys to access the next r
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摘要：A 3 x 3 magic square is a 3 x 3 grid filled with distinct numbers from 1 to 9 such that each row, column, and both diagonals all have the same sum. Gi
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摘要：There are n dominoes in a line, and we place each domino vertically upright. In the beginning, we simultaneously push some of the dominoes either to t
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摘要：Alice plays the following game, loosely based on the card game "21". Alice starts with 0 points, and draws numbers while she has less than K points. D
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摘要：A rectangle is represented as a list [x1, y1, x2, y2], where (x1, y1) are the coordinates of its bottom-left corner, and (x2, y2) are the coordinates
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摘要：Your car starts at position 0 and speed +1 on an infinite number line. (Your car can go into negative positions.) Your car drives automatically accord
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摘要：Two images A and B are given, represented as binary, square matrices of the same size. (A binary matrix has only 0s and 1s as values.) We translate on
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摘要：To some string S, we will perform some replacement operations that replace groups of letters with new ones (not necessarily the same size). Each repla
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摘要：Given a binary matrix A, we want to flip the image horizontally, then invert it, and return the resulting image. To flip an image horizontally means t
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摘要：We are given a personal information string S, which may represent either an email address or a phone number. We would like to mask this personal infor
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摘要：In a string S of lowercase letters, these letters form consecutive groups of the same character. For example, a string like S = "abbxxxxzyy" has the g
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摘要：Given a set of N people (numbered 1, 2, ..., N), we would like to split everyone into two groups of any size. Each person may dislike some other peopl
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摘要：The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding one
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摘要：We have a list of bus routes. Each routes[i] is a bus route that the i-th bus repeats forever. For example if routes[0] = [1, 5, 7], this means that t
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摘要：In a given integer array A, we must move every element of A to either list B or list C. (B and C initially start empty.) Return true if and only if af
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摘要：We have jobs: difficulty[i] is the difficulty of the ith job, and profit[i] is the profit of the ith job. Now we have some workers. worker[i] is the a
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