随笔分类 - LeetCode
摘要：We have a sequence of books: the i-th book has thickness books[i][0] and height books[i][1]. We want to place these books in order onto bookcase shelv
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摘要：In an infinite binary tree where every node has two children, the nodes are labelled in row order. In the odd numbered rows (ie., the first, third, fi
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摘要：We distribute some number of candies, to a row of n = num_people people in the following way: We then give 1 candy to the first person, 2 candies to t
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摘要：Under a grammar given below, strings can represent a set of lowercase words. Let's use R(expr) to denote the set of words the expression represents. G
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摘要：(This problem is an interactive problem.) You may recall that an array A is a mountain array if and only if: A.length >= 3 There exists some i with 0
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摘要：You are driving a vehicle that has capacity empty seats initially available for passengers. The vehicle only drives east (ie. it cannot turn around an
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摘要：You are given a large sample of integers in the range [0, 255]. Since the sample is so large, it is represented by an array count where count[k] is th
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摘要：Given two strings str1 and str2, return the shortest string that has both str1 and str2 as subsequences. If multiple answers exist, you may return any
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摘要：Given an n x n binary matrix grid, return the length of the shortest clear path in the matrix. If there is no clear path, return -1. A clear path in a
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摘要：We have a set of items: the i-th item has value values[i] and label labels[i]. Then, we choose a subset S of these items, such that: |S| <= num_wanted
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摘要：Given a fixed length array arr of integers, duplicate each occurrence of zero, shifting the remaining elements to the right. Note that elements beyond
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摘要：We can rotate digits by 180 degrees to form new digits. When 0, 1, 6, 8, 9 are rotated 180 degrees, they become 0, 1, 9, 8, 6 respectively. When 2, 3,
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摘要：On a campus represented as a 2D grid, there are N workers and M bikes, with N <= M. Each worker and bike is a 2D coordinate on this grid. Our goal is
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摘要：Given a number N, return true if and only if it is a confusing number, which satisfies the following condition: We can rotate digits by 180 degrees to
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摘要：From any string, we can form a subsequence of that string by deleting some number of characters (possibly no deletions). Given two strings source and
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摘要：Return the lexicographically smallest subsequence of s that contains all the distinct characters of s exactly once. Note: This question is the same as
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摘要：Given the root of a binary tree, consider all root to leaf paths: paths from the root to any leaf. (A leaf is a node with no children.) A node is insu
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摘要：You have n tiles, where each tile has one letter tiles[i] printed on it. Return the number of possible non-empty sequences of letters you can make usi
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摘要：Given words first and second, consider occurrences in some text of the form "first second third", where second comes immediately after first, and thir
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摘要：Given a matrix and a target, return the number of non-empty submatrices that sum to target. A submatrix x1, y1, x2, y2 is the set of all cells matrix[
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