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Given an array of integers arr, and three integers a, b and c. You need to find the number of good triplets. A triplet (arr[i], arr[j], arr[k]) is goo 阅读全文
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Given a 0-indexed integer array nums, return the number of distinct quadruplets (a, b, c, d) such that: nums[a] + nums[b] + nums[c] == nums[d], and a 阅读全文
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Design a max stack data structure that supports the stack operations and supports finding the stack's maximum element. Implement the MaxStack class: M 阅读全文
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You are given an integer array nums. You want to maximize the number of points you get by performing the following operation any number of times: Pick 阅读全文
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You have a 2-D grid of size m x n representing a box, and you have n balls. The box is open on the top and bottom sides. Each cell in the box has a di 阅读全文
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There are n dominoes in a line, and we place each domino vertically upright. In the beginning, we simultaneously push some of the dominoes either to t 阅读全文
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There are n houses evenly lined up on the street, and each house is beautifully painted. You are given a 0-indexed integer array colors of length n, w 阅读全文
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Given a 0-indexed integer array nums of size n, find the maximum difference between nums[i] and nums[j] (i.e., nums[j] - nums[i]), such that 0 <= i < 阅读全文
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You are given two strings s1 and s2 of equal length. A string swap is an operation where you choose two indices in a string (not necessarily different 阅读全文
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You are given an array nums of n positive integers. You can perform two types of operations on any element of the array any number of times: If the el 阅读全文
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We have two special characters: The first character can be represented by one bit 0. The second character can be represented by two bits (10 or 11). G 阅读全文
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You are given two integers, x and y, which represent your current location on a Cartesian grid: (x, y). You are also given an array points where each 阅读全文
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Given an integer n, return a list of all simplified fractions between 0 and 1 (exclusive) such that the denominator is less-than-or-equal-to n. You ca 阅读全文
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You are given an array of unique integers salary where salary[i] is the salary of the ith employee. Return the average salary of employees excluding t 阅读全文
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Given two non-negative integers low and high. Return the count of odd numbers between low and high (inclusive). Example 1: Input: low = 3, high = 7 Ou 阅读全文
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Given a 0-indexed string word and a character ch, reverse the segment of word that starts at index 0 and ends at the index of the first occurrence of 阅读全文
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You are given an integer array nums. The unique elements of an array are the elements that appear exactly once in the array. Return the sum of all the 阅读全文
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You are given an array rectangles where rectangles[i] = [li, wi] represents the ith rectangle of length li and width wi. You can cut the ith rectangle 阅读全文
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A string s is nice if, for every letter of the alphabet that s contains, it appears both in uppercase and lowercase. For example, "abABB" is nice beca 阅读全文
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You are playing a game that contains multiple characters, and each of the characters has two main properties: attack and defense. You are given a 2D i 阅读全文