Jackson.tmm

LeetCode 2130 - Maximum Twin Sum of a Linked List In a linked list of size n, where n is even, the ith node (0-indexed) of the linked list is known as the twin of the (n-1-i)th node, if 0 <= i <= (n / 2) - 1. For example, if n = 4, then node 0 is the twin of node 3, and node 1 is the twin of

LeetCode 718 - Maximum Length of Repeated Subarray Given two integer arrays ``nums1andnums2`, return the maximum length of a subarray that appears in both arrays. Input: nums1 = [1,2,3,2,1], nums2 = [3,2,1,4,7] Output: 3 Explanation: The repeated subarray with maximum length is [3,2,1]. Input: nums1 = [0,0,0,0,0], nums2 = [0,0,0,0,0] Output: 5 How can we solve this problem? 這題要我們找出2個arr

LeetCode 42 - Trapping Rain Water Given a list paths of directory info, including the directory path, and all the files with contents in this directory, return all the duplicate files in the file system in terms of their paths. You may return the answer in any order. A group of duplicate files consists of at least two files that have the same content. A single directory info string in

LeetCode 42 - Trapping Rain Water Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. example Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: The above elevation map (black section) is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped. Input: height = [4,2,0,3,2,5] Output: 9 How

LeetCode 336 - Palindrome Pairs Given a list of unique words, return all the pairs of the distinct indices (i, j) in the given list, so that the concatenation of the two words words[i] + words[j] is a palindrome. example Input: words = ["abcd","dcba","lls","s","sssll"] Output: [[0,1],[1,0],[3,2],[2,4]] Explanation: The palindromes are ["dcbaabcd","abcddcba","slls","llssssll"] Input: words = ["bat","tab","cat"] Output: [[0,1],[1,0]] Explanation: The palindromes are ["battab","tabbat"] How can we solve this problem? 在解

LeetCode 1770 - Maximum Score from Performing Multiplication Operations You are given two integer arrays nums and multipliers of size n and m respectively, where n >= m. The arrays are 1-indexed. You begin with a score of 0. You want to perform exactly m operations. On the ith operation (1-indexed), you will: Choose one integer x from either the start or the end of the array nums. Add multipliers[i]

LeetCode 969 - Pancake Sorting Given an array of integers arr, sort the array by performing a series of pancake flips. In one pancake flip we do the following steps: Choose an integer k where 1 <= k <= arr.length. Reverse the sub-array arr[0...k-1] (0-indexed). For example, if arr = [3,2,1,4] and we performed a pancake flip choosing k = 3, we reverse the sub-array [3,2,1], so arr = [1,2,3,4]

LeetCode 2007 - Find Original Array From Doubled Array An integer array original is transformed into a doubled array changed by appending twice the value of every element in original, and then randomly shuffling the resulting array. Given an array changed, return original if changed is a doubled array. If changed is not a doubled array, return an empty array. The elements in original may be returned in any order.

LeetCode 1457 - Pseudo-Palindromic Paths in a Binary Tree Given a binary tree where node values are digits from 1 to 9. A path in the binary tree is said to be pseudo-palindromic if at least one permutation of the node values in the path is a palindrome. Return the number of pseudo-palindromic paths going from the root node to leaf nodes. example Input: root = [2,3,1,3,1,null,1] Output: 2 Explanation:

LeetCode 393 - UTF-8 Validation Given an integer array data representing the data, return whether it is a valid UTF-8 encoding (i.e. it translates to a sequence of valid UTF-8 encoded characters). A character in UTF8 can be from 1 to 4 bytes long, subjected to the following rules: For a 1-byte character, the first bit is a 0, followed by its Unicode code. For an n-bytes character, the first