Ens

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". The only good substring of length 3 is "xyz". Example 2: Input: s = "aababcabc" Output: 4 Explanation: There are 7 substrings of size 3: "aab", "aba", "bab", "abc", "bca", "cab", and "abc". The good substrings are "abc", "bca", "cab", and "abc". Constraints: ...

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: ...

221. Maximal Square Given an m x n binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s and return its area. 1 2 3 4 Example 1: Input: matrix = [["1","0","1","0","0"],["1","0","1","1","1"],["1","1","1","1","1"],["1","0","0","1","0"]] Output: 4 1 2 3 4 Example 2: Input: matrix = [["0","1"],["1","0"]] Output: 1 1 2 3 4 Example 3: Input: matrix = [["0"]] Output: 0 Constraints: ...

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: ...

938. Range Sum of BST Given the root node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high]. 1 2 3 4 5 Example 1: Input: root = [10,5,15,3,7,null,18], low = 7, high = 15 Output: 32 Explanation: Nodes 7, 10, and 15 are in the range [7, 15]. 7 + 10 + 15 = 32. ...

472. Concatenated Words Given an array of strings words (without duplicates), return all the concatenated words in the given list of words. A concatenated word is defined as a string that is comprised entirely of at least two shorter words in the given array. 1 2 3 4 5 6 7 8 9 10 11 12 Example 1: Input: words = ["cat","cats","catsdogcats","dog","dogcatsdog","hippopotamuses","rat","ratcatdogcat"] Output: ["catsdogcats","dogcatsdog","ratcatdogcat"] Explanation: "catsdogcats" can be concatenated by "cats", "dog" and "cats"; "dogcatsdog" can be concatenated by "dog", "cats" and "dog"; "ratcatdogcat" can be concatenated by "rat", "cat", "dog" and "cat". Example 2: Input: words = ["cat","dog","catdog"] Output: ["catdog"] Constraints: ...

216. Combination Sum III Find all valid combinations of k numbers that sum up to n such that the following conditions are true: Only numbers 1 through 9 are used. Each number is used at most once. Return a list of all possible valid combinations. The list must not contain the same combination twice, and the combinations may be returned in any order. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 Example 1: Input: k = 3, n = 7 Output: [[1,2,4]] Explanation: 1 + 2 + 4 = 7 There are no other valid combinations. Example 2: Input: k = 3, n = 9 Output: [[1,2,6],[1,3,5],[2,3,4]] Explanation: 1 + 2 + 6 = 9 1 + 3 + 5 = 9 2 + 3 + 4 = 9 There are no other valid combinations. Example 3: Input: k = 4, n = 1 Output: [] Explanation: There are no valid combinations. [1,2,1] is not valid because 1 is used twice. Example 4: Input: k = 3, n = 2 Output: [] Explanation: There are no valid combinations. Example 5: Input: k = 9, n = 45 Output: [[1,2,3,4,5,6,7,8,9]] Explanation: 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45 ​​​​​​​There are no other valid combinations. Constraints: ...

39. Combination Sum Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. You may return the combinations in any order. The same number may be chosen from candidates an unlimited number of times. Two combinations are unique if the frequency of at least one of the chosen numbers is different. It is guaranteed that the number of unique combinations that sum up to target is less than 150 combinations for the given input. ...

40. Combination Sum II Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to target. Each number in candidates may only be used once in the combination. Note: The solution set must not contain duplicate combinations. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Example 1: Input: candidates = [10,1,2,7,6,1,5], target = 8 Output: [ [1,1,6], [1,2,5], [1,7], [2,6] ] Example 2: Input: candidates = [2,5,2,1,2], target = 5 Output: [ [1,2,2], [5] ] Constraints: ...