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2353. Design a Food Rating System
#Problem Design a food rating system that can do the following: Modify the rating of a food item listed in the system. Return the highest-rated food item for a type of cuisine in the system. Implement the FoodRatings class: …
873. Length of Longest Fibonacci Subsequence
#Problem A sequence x₁, x₂, ..., xₙ is Fibonacci-like if: n >= 3 xᵢ + xᵢ₊₁ == xᵢ₊₂ for all i + 2 <= n Given a strictly increasing array arr of positive integers forming a sequence, return the length of the longest Fibonacci-like subsequence …
1524. Number of Sub-arrays With Odd Sum
#Problem Given an array of integers arr, return the number of subarrays with an odd sum. Since the answer can be very large, return it modulo 10⁹ + 7. https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum/ Example 1: Input: arr = …
1749. Maximum Absolute Sum of Any Subarray
#Problem You are given an integer array nums. The absolute sum of a subarray [numsₗ, numsₗ₊₁, ..., numsᵣ₋₁, numsᵣ] is abs(numsₗ + numsₗ₊₁ + ... + numsᵣ₋₁ + numsᵣ). Return the maximum absolute sum of any (possibly empty) subarray of nums. …
1472. Design Browser History
#Problem You have a browser of one tab where you start on the homepage and you can visit another url, get back in the history number of steps or move forward in the history number of steps. Implement the BrowserHistory class: …
2502. Design Memory Allocator
#Problem You are given an integer n representing the size of a 0-indexed memory array. All memory units are initially free. You have a memory allocator with the following functionalities: Allocate a block of size consecutive free memory …
2467. Most Profitable Path in a Tree
#Problem There is an undirected tree with n nodes labeled from 0 to n - 1, rooted at node 0. You are given a 2D integer array edges of length n - 1 where edges[i] = [aᵢ, bᵢ] indicates that there is an edge between nodes aᵢ and bᵢ in the …
889. Construct Binary Tree from Preorder and Postorder Traversal
#Problem Given two integer arrays, preorder and postorder where preorder is the preorder traversal of a binary tree of distinct values and postorder is the postorder traversal of the same tree, reconstruct and return the binary tree. If …
1261. Find Elements in a Contaminated Binary Tree
#Problem Given a binary tree with the following rules: root.val == 0 For any treeNode: If treeNode.val has a value x and treeNode.left != null, then treeNode.left.val == 2 * x + 1 If treeNode.val has a value x and treeNode.right != null, …
1980. Find Unique Binary String
#Problem Given an array of strings nums containing n unique binary strings each of length n, return a binary string of length n that does not appear in nums. If there are multiple answers, you may return any of them. …
2944. Minimum Number of Coins for Fruits
#Problem You are given an 0-indexed integer array prices where prices[i] denotes the number of coins needed to purchase the (i + 1)ᵗʰ fruit. The fruit market has the following reward for each fruit: If you purchase the (i + 1)ᵗʰ fruit at …
1415. The k-th Lexicographical String of All Happy Strings of Length n
#Problem A happy string is a string that: consists only of letters of the set ['a', 'b', 'c']. s[i] != s[i + 1] for all values of i from 1 to s.length - 1 (string is 1-indexed). For example, strings “abc”, “ac”, “b” and “abcbabcbcb” are all …
624. Maximum Distance in Arrays
#Problem You are given m arrays, where each array is sorted in ascending order. You can pick up two integers from two different arrays (each array picks one) and calculate the distance. We define the distance between two integers a and b to …
2375. Construct Smallest Number From DI String
#Problem You are given a 0-indexed string pattern of length n consisting of the characters 'I' meaning increasing and 'D' meaning decreasing. A 0-indexed string num of length n + 1 is created using the following conditions: num consists of …
2080. Range Frequency Queries
#Problem Design a data structure to find the frequency of a given value in a given subarray. The frequency of a value in a subarray is the number of occurrences of that value in the subarray. Implement the RangeFreqQuery class: …
1079. Letter Tile Possibilities
#Problem 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 using the letters printed on those tiles. …
1718. Construct the Lexicographically Largest Valid Sequence
#Problem Given an integer n, find a sequence that satisfies all of the following: The integer 1 occurs once in the sequence. Each integer between 2 and n occurs twice in the sequence. For every integer i between 2 and n, the distance …
2698. Find the Punishment Number of an Integer
#Problem Given a positive integer n, return the punishment number of n. The punishment number of n is defined as the sum of the squares of all integers i such that: 1 <= i <= n The decimal representation of i * i can be partitioned into …
1706. Where Will the Ball Fall
#Problem 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 diagonal board spanning two corners of the cell that can redirect a ball to the …
1352. Product of the Last K Numbers
#Problem Design an algorithm that accepts a stream of integers and retrieves the product of the last k integers of the stream. Implement the ProductOfNumbers class: ProductOfNumbers() Initializes the object with an empty stream. void …
1552. Magnetic Force Between Two Balls
#Problem In the universe Earth C-137, Rick discovered a special form of magnetic force between two balls if they are put in his new invented basket. Rick has n empty baskets, the iᵗʰ basket is at position[i], Morty has m balls and needs to …
2342. Max Sum of a Pair With Equal Sum of Digits
#Problem You are given a 0-indexed array nums consisting of positive integers. You can choose two indices i and j, such that i != j, and the sum of digits of the number nums[i] is equal to that of nums[j]. Return the maximum value of …
1910. Remove All Occurrences of a Substring
#Problem Given two strings s and part, perform the following operation on s until all occurrences of the substring part are removed: Find the leftmost occurrence of the substring part and remove it from s. Return s after removing all …
2364. Count Number of Bad Pairs
#Problem You are given a 0-indexed integer array nums. A pair of indices (i, j) is a bad pair if i < j and j - i != nums[j] - nums[i]. Return the total number of bad pairs in nums. https://leetcode.com/problems/count-number-of-bad-pairs/ …
80. Remove Duplicates from Sorted Array II
#Problem Given an integer array nums sorted in non-decreasing order, remove some duplicates in-place such that each unique element appears at most twice. The relative order of the elements should be kept the same. Since it is impossible to …
2349. Design a Number Container System
#Problem Design a number container system that can do the following: Insert or Replace a number at the given index in the system. Return the smallest index for the given number in the system. Implement the NumberContainers class: …
63. Unique Paths II
#Problem You are given an m x n integer array grid. There is a robot initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-right corner (i.e., grid[m - 1][n - 1]). The robot can only move either …
3160. Find the Number of Distinct Colors Among the Balls
#Problem You are given an integer limit and a 2D array queries of size n x 2. There are limit + 1 balls with distinct labels in the range [0, limit]. Initially, all balls are uncolored. For every query in queries that is of the form [x, y], …
1726. Tuple with Same Product
#Problem Given an array nums of distinct positive integers, return the number of tuples (a, b, c, d) such that a * b = c * d where a, b, c, and d are elements of nums, and a != b != c != d. …
81. Search in Rotated Sorted Array II
#Problem There is an integer array nums sorted in non-decreasing order (not necessarily with distinct values). Before being passed to your function, nums is rotated at an unknown pivot index k (0 <= k < nums.length) such that the resulting …
2658. Maximum Number of Fish in a Grid
#Problem You are given a 0-indexed 2D matrix grid of size m x n, where (r, c) represents: A land cell if grid[r][c] = 0, or A water cell containing grid[r][c] fish, if grid[r][c] > 0. A fisher can start at any water cell (r, c) and can do …
1462. Course Schedule IV
#Problem There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [aᵢ, bᵢ] indicates that you must take course aᵢ first if you want to take …