随笔分类 - LeetCode
摘要：Given an array of integers A with even length, return true if and only if it is possible to reorder it such that A[2 * i + 1] = 2 * A[2 * i] for every
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摘要：In an alien language, surprisingly they also use english lowercase letters, but possibly in a different order. The order of the alphabet is some permu
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摘要：Given a non-empty array of unique positive integers A, consider the following graph: There are A.length nodes, labelled A[0] to A[A.length - 1]; There
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摘要：For a binary tree T, we can define a flip operation as follows: choose any node, and swap the left and right child subtrees. A binary tree X is flip e
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摘要：In a deck of cards, every card has a unique integer. You can order the deck in any order you want. Initially, all the cards start face down (unreveale
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摘要：Given an array of 4 digits, return the largest 24 hour time that can be made. The smallest 24 hour time is 00:00, and the largest is 23:59. Starting f
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摘要：You have an initial power P, an initial score of 0 points, and a bag of tokens. Each token can be used at most once, has a value token[i], and has pot
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摘要：On a 2D plane, we place stones at some integer coordinate points. Each coordinate point may have at most one stone. Now, a move consists of removing a
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摘要：Given two sequences pushed and popped with distinct values, return true if and only if this could have been the result of a sequence of push and pop o
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摘要：Given an array of integers A, a move consists of choosing any , and incrementing it by . Return the least number of moves to make every value in uniqu
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摘要：We are given an array of lowercase letter strings, all of the same length. Now, we may choose any set of deletion indices, and for each string, we del
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摘要：Given an array A of strings, find any smallest string that contains each string in A as a substring. We may assume that no string in A is substring of
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摘要：Given a string that only contains "I" (increase) or "D" (decrease), let . Return any permutation of such that for all : If , then Example 1: Example 2
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摘要：Given an array of integers, return if and only if it is a valid mountain array . Recall that A is a mountain array if and only if: There exists some w
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摘要：Given a string , count the number of distinct, non empty subsequences of . Since the result may be large, return the answer modulo . Example 1: Exampl
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摘要：Given a set of points in the xy plane, determine the minimum area of a rectangle formed from these points, with sides parallel to the x and y axes. If
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摘要：Given the node of a binary search tree, return the sum of values of all nodes with value between and (inclusive). The binary search tree is guaranteed
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摘要：You have an array of . Each log is a space delimited string of words. For each log, the first word in each log is an alphanumeric identifier . Then, e
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摘要：You want to form a string of lowercase letters. At the beginning, your sequence is `'?' stamp` of lowercase letters. On each turn, you may place the s
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摘要：The chess knight has a unique movement, it may move two squares vertically and one square horizontally, or two squares horizontally and one square ver
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