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1 """ 2 Determine if a 9x9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: 3 Each row must contain 阅读全文
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1 """ 2 There are N gas stations along a circular route, where the amount of gas at station i is gas[i]. 3 You have a car with an unlimited gas tank a 阅读全文
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1 """ 2 Given a 2D board containing 'X' and 'O' (the letter O), capture all regions surrounded by 'X'. 3 A region is captured by flipping all 'O's int 阅读全文
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1 """ 2 Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. 3 T 阅读全文
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1 """ 2 Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: 3 Integers in each row ar 阅读全文
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1 """ 2 Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must 阅读全文
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1 """ 2 Given an unsorted array nums, reorder it such that nums[0] < nums[1] > nums[2] < nums[3].... 3 Example 1: 4 Input: nums = [1, 5, 1, 1, 6, 4] 5 阅读全文
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1 """ 2 Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and put. 3 get(key) 阅读全文
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1 """ 2 Implement a basic calculator to evaluate a simple expression string. 3 The expression string contains only non-negative integers, +, -, *, / o 阅读全文
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1 """ 2 Given a non-empty array of digits representing a non-negative integer, plus one to the integer. 3 The digits are stored such that the most sig 阅读全文