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1013. Partition Array Into Three Parts With Equal Sum Given an array of integers arr, return true if we can partition the array into three non-empty parts with equal sums. Formally, we can partition the array if we can find indexes i + 1 < j with (arr[0] + arr[1] + … + arr[i] == arr[i + 1] + arr[i + 2] + … + arr[j - 1] == arr[j] + arr[j + 1] + … + arr[arr....

243. Shortest Word Distance Given an array of strings wordsDict and two different strings that already exist in the array word1 and word2, return the shortest distance between these two words in the list. 1 2 3 4 5 6 7 8 9 Example 1: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "coding", word2 = "practice" Output: 3 Example 2: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "makes", word2 = "coding" Output: 1 Constraints:...

244. Shortest Word Distance II Design a data structure that will be initialized with a string array, and then it should answer queries of the shortest distance between two different strings from the array. Implement the WordDistance class: WordDistance(String[] wordsDict) initializes the object with the strings array wordsDict. int shortest(String word1, String word2) returns the shortest distance between word1 and word2 in the array wordsDict. 1 2 3 4 5 6 7 8 9 10 11 12 Example 1: Input ["WordDistance", "shortest", "shortest"] [[["practice", "makes", "perfect", "coding", "makes"]], ["coding", "practice"], ["makes", "coding"]] Output [null, 3, 1] Explanation WordDistance wordDistance = new WordDistance(["practice", "makes", "perfect", "coding", "makes"]); wordDistance....

245. Shortest Word Distance III Given an array of strings wordsDict and two strings that already exist in the array word1 and word2, return the shortest distance between these two words in the list. Note that word1 and word2 may be the same. It is guaranteed that they represent two individual words in the list. 1 2 3 4 5 6 7 8 9 Example 1: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "makes", word2 = "coding" Output: 1 Example 2: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "makes", word2 = "makes" Output: 3 Constraints:...

835. Image Overlap You are given two images img1 and img2 both of size n x n, represented as binary, square matrices of the same size. (A binary matrix has only 0s and 1s as values.) We translate one image however we choose (sliding it left, right, up, or down any number of units), and place it on top of the other image. After, the overlap of this translation is the number of positions that have a 1 in both images....

832. Flipping an Image Given an n x n binary matrix image, flip the image horizontally, then invert it, and return the resulting image. To flip an image horizontally means that each row of the image is reversed. For example, flipping [1,1,0] horizontally results in [0,1,1]. To invert an image means that each 0 is replaced by 1, and each 1 is replaced by 0. For example, inverting [0,1,1] results in [1,0,0]....

1441. Build an Array With Stack Operations Given an array target and an integer n. In each iteration, you will read a number from list = {1,2,3…, n}. Build the target array using the following operations: Push: Read a new element from the beginning list, and push it in the array. Pop: delete the last element of the array. If the target array is already built, stop reading more elements. Return the operations to build the target array....

1041. Robot Bounded In Circle On an infinite plane, a robot initially stands at (0, 0) and faces north. The robot can receive one of three instructions: “G”: go straight 1 unit; “L”: turn 90 degrees to the left; “R”: turn 90 degrees to the right. The robot performs the instructions given in order, and repeats them forever. Return true if and only if there exists a circle in the plane such that the robot never leaves the circle....

189. Rotate Array Given an array, rotate the array to the right by k steps, where k is non-negative. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Example 1: Input: nums = [1,2,3,4,5,6,7], k = 3 Output: [5,6,7,1,2,3,4] Explanation: rotate 1 steps to the right: [7,1,2,3,4,5,6] rotate 2 steps to the right: [6,7,1,2,3,4,5] rotate 3 steps to the right: [5,6,7,1,2,3,4] Example 2: Input: nums = [-1,-100,3,99], k = 2 Output: [3,99,-1,-100] Explanation: rotate 1 steps to the right: [99,-1,-100,3] rotate 2 steps to the right: [3,99,-1,-100] Constraints:...

1876. Substrings of Size Three with Distinct Characters A string is good if there are no repeated characters. Given a string s​​​​​, return the number of good substrings of length three in s​​​​​​. Note that if there are multiple occurrences of the same substring, every occurrence should be counted. A substring is a contiguous sequence of characters in a string. 1 2 3 4 5 6 7 8 9 10 11 12 13 Example 1: Input: s = "xyzzaz" Output: 1 Explanation: There are 4 substrings of size 3: "xyz", "yzz", "zza", and "zaz"....

1877. Minimize Maximum Pair Sum in Array The pair sum of a pair (a,b) is equal to a + b. The maximum pair sum is the largest pair sum in a list of pairs. For example, if we have pairs (1,5), (2,3), and (4,4), the maximum pair sum would be max(1+5, 2+3, 4+4) = max(6, 5, 8) = 8. Given an array nums of even length n, pair up the elements of nums into n / 2 pairs such that:...

1878. Get Biggest Three Rhombus Sums in a Grid You are given an m x n integer matrix grid​​​. A rhombus sum is the sum of the elements that form the border of a regular rhombus shape in grid​​​. The rhombus must have the shape of a square rotated 45 degrees with each of the corners centered in a grid cell. Below is an image of four valid rhombus shapes with the corresponding colored cells that should be included in each rhombus sum:...

1852. Distinct Numbers in Each Subarray Given an integer array nums and an integer k, you are asked to construct the array ans of size n-k+1 where ans[i] is the number of distinct numbers in the subarray nums[i:i+k-1] = [nums[i], nums[i+1], …, nums[i+k-1]]. Return the array ans. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Example 1: Input: nums = [1,2,3,2,2,1,3], k = 3 Output: [3,2,2,2,3] Explanation: The number of distinct elements in each subarray goes as follows: - nums[0:2] = [1,2,3] so ans[0] = 3 - nums[1:3] = [2,3,2] so ans[1] = 2 - nums[2:4] = [3,2,2] so ans[2] = 2 - nums[3:5] = [2,2,1] so ans[3] = 2 - nums[4:6] = [2,1,3] so ans[4] = 3 Example 2: Input: nums = [1,1,1,1,2,3,4], k = 4 Output: [1,2,3,4] Explanation: The number of distinct elements in each subarray goes as follows: - nums[0:3] = [1,1,1,1] so ans[0] = 1 - nums[1:4] = [1,1,1,2] so ans[1] = 2 - nums[2:5] = [1,1,2,3] so ans[2] = 3 - nums[3:6] = [1,2,3,4] so ans[3] = 4 Constraints:...

66. Plus One Given a non-empty array of decimal digits representing a non-negative integer, increment one to the integer. The digits are stored such that the most significant digit is at the head of the list, and each element in the array contains a single digit. You may assume the integer does not contain any leading zero, except the number 0 itself. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Example 1: Input: digits = [1,2,3] Output: [1,2,4] Explanation: The array represents the integer 123....

1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold Given an array of integers arr and two integers k and threshold. Return the number of sub-arrays of size k and average greater than or equal to threshold. 1 2 3 4 5 Example 1: Input: arr = [2,2,2,2,5,5,5,8], k = 3, threshold = 4 Output: 3 Explanation: Sub-arrays [2,5,5],[5,5,5] and [5,5,8] have averages 4, 5 and 6 respectively....