随笔分类 - LeetCode
摘要：We are given a 2-dimensional grid. "." is an empty cell, "#" is a wall, "@" is the starting point, ("a", "b", ...) are keys, and ("A", "B", ...) are l
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摘要：Let's say a positive integer is a *superpalindrome* if it is a palindrome, and it is also the square of a palindrome. Now, given two positive integers
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摘要：A car travels from a starting position to a destination which is miles east of the starting position. Along the way, there are gas stations. Each repr
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摘要：Given an array of non negative integers, return an array consisting of all the even elements of , followed by all the odd elements of . You may return
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摘要：We run a preorder depth first search on the rootof a binary tree. At each node in this traversal, we output D dashes (where D is the depth of this nod
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摘要：A positive integer is magical if it is divisible by either A or B. Return the N th magical number. Since the answer may be very large, return it modul
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摘要：In a row of trees, the th tree produces fruit with type . You start at any tree of your choice, then repeatedly perform the following steps: 1. Add on
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摘要：There are G people in a gang, and a list of various crimes they could commit. The th crime generates a and requires gang members to participate. If a
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摘要：We are given , a length string of characters from the set . (These letters stand for "decreasing" and "increasing".) A valid permutation is a permutat
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摘要：Starting with an undirected graph (the "original graph") with nodes from to , subdivisions are made to some of the edges. The graph is given as follow
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摘要：We have a sorted set of digits D, a non-empty subset of {'1','2','3','4','5','6','7','8','9'}. (Note that '0' is not included.) Now, we write numbers
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摘要：You are given eggs, and you have access to a building with floors from to . Each egg is identical in function, and if an egg breaks, you cannot drop i
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摘要：Write a class which collects daily price quotes for some stock, and returns the span of that stock's price for the current day. The span of the stock'
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摘要：Given an array of integers , consider all non empty subsequences of . For any sequence S, let the width of S be the difference between the maximum and
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摘要：Write an iterator that iterates through a run length encoded sequence. The iterator is initialized by , where is a run length encoding of some sequenc
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摘要：A string of lowercase letters is given. Then, we may make any number of moves . In each move, we choose one of the first letters (starting from the le
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摘要：Implement , a class which simulates the operation of a stack like data structure. has two functions: , which pushes an integer onto the stack. , which
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摘要：We have an array A of non-negative integers. For every (contiguous) subarray B = [A[i], A[i+1], ..., A[j]] (with i <= j), we take the bitwise OR of al
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摘要：Given a tree, rearrange the tree in in-order so that the leftmost node in the tree is now the root of the tree, and every node has no left child and o
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摘要：An array is monotonic if it is either monotone increasing or monotone decreasing. An array is monotone increasing if for all . Return if and only if t
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