原创 362. Design Hit Counter
Design a hit counter which counts the number of hits received in the past 5 minutes. Each function accepts a timesta
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原创 444. Sequence Reconstruction
Check whether the original sequence org can be uniquely reconstructed from the sequences in seqs. The org sequence
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原创 307. Range Sum Query - Mutable
Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. The update(i, v
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原创 130. Surrounded Regions
Given a 2D board containing 'X' and 'O' (the letter O), capture all regions surrounded by 'X'. A region is captured
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原创 310. Minimum Height Trees
For a undirected graph with tree characteristics, we can choose any node as the root. The result graph is then a root
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原创 379. Design Phone Directory
Design a Phone Directory which supports the following operations: get: Provide a number which is not assigned to an
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原创 398. Random Pick Index
Given an array of integers with possible duplicates, randomly output the index of a given target number. You can assu
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原创 286. Walls and Gates
You are given a m x n 2D grid initialized with these three possible values. -1 - A wall or an obstacle.0 - A gate.INF
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原创 382. Linked List Random Node
Given a singly linked list, return a random node's value from the linked list. Each node must have the same probabili
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原创 399. Evaluate Division
Equations are given in the format A / B = k, where A and B are variables represented as strings, and k is a real nu
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原创 284. Peeking Iterator
Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that su
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原创 348. Design Tic-Tac-Toe
Design a Tic-tac-toe game that is played between two players on a n x n grid. You may assume the following rules: A
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原创 388. Longest Absolute File Path
Suppose we abstract our file system by a string in the following manner: The string "dir\n\tsubdir1\n\tsubdir2\n\t\t
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原创 560. Subarray Sum Equals K
Given an array of integers and an integer k, you need to find the total number of continuous subarrays whose sum equa
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原创 604. Design Compressed String Iterator
Design and implement a data structure for a compressed string iterator. It should support the following operations: n
2020-02-22 19:51:46