Jackson.tmm

LeetCode 948 - Bag of Tokens You have an initial power of power, an initial score of 0, and a bag of tokens where tokens[i] is the value of the ith token (0-indexed). Your goal is to maximize your total score by potentially playing each token in one of two ways: If your current power is at least tokens[i], you may play the ith token face up, losing tokens[i]power and

LeetCode 1996 - The Number of Weak Characters in the Game 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 integer array properties where properties[i] = [attacki, defensei] represents the properties of the ith character in the game. A character is said to be weak if any other character has both attack and

LeetCode 94 - Binary Tree Inorder Traversal Given the root of a binary tree, return the inorder traversal of its nodes’ values. example Input: root = [1,null,2,3] Output: [1,3,2] Input: root = [] Output: [] Input: root = [1] Output: [1] How can we solve this problem? 這題很簡單,只要使用中序遍歷即可。 Solution: /** * Definition for a

LeetCode 606 - Construct String from Binary Tree Given the root of a binary tree, construct a string consisting of parenthesis and integers from a binary tree with the preorder traversal way, and return it. Omit all the empty parenthesis pairs that do not affect the one-to-one mapping relationship between the string and the original binary tree. example Input: root = [1,2,3,4] Output: "1(2(4))(3)" Explanation: Originally, it needs to be

LeetCode 442 - Find All Duplicates in an Array Given an integer array nums of length n where all the integers of nums are in the range [1, n] and each integer appears once or twice, return an array of all the integers that appears twice. You must write an algorithm that runs in O(n) time and uses only constant extra space. example Input: nums = [4,3,2,7,8,2,3,1] Output: [2,3] Input:

LeetCode 2196 - Create Binary Tree From Descriptions You are given a 2D integer array descriptions where descriptions[i] = [parenti, childi, isLefti] indicates that parenti is the parent of childi in a binary tree of unique values. Furthermore, If isLefti == 1, then childi is the left child of parenti. If isLefti == 0, then childi is the right child of parenti. Construct the binary tree described by descriptions and

LeetCode 814 - Binary Tree Pruning Given the root of a binary tree, return the same tree where every subtree (of the given tree) not containing a 1 has been removed. A subtree of a node node is node plus every node that is a descendant of node. example Input: root = [1,null,0,0,1] Output: [1,null,0,null,1] Explanation: Only the red nodes satisfy the property "every subtree not containing a 1". The

LeetCode 92 - Reverse Linked List II Given the head of a singly linked list and two integers left and right where left <= right, reverse the nodes of the list from position left to position right, and return the reversed list. example Input: head = [1,2,3,4,5], left = 2, right = 4 Output: [1,4,3,2,5] Input: head = [5], left = 1, right = 1 Output: [5] How can we

這題主要是學習DP思想，做個小記錄 LeetCode 629 - K Inverse Pairs Array For an integer array nums, an inverse pair is a pair of integers [i, j] where 0 <= i < j < nums.length and nums[i] > nums[j]. Given two integersn and k, return the number of different arrays consist of numbers from 1 to n such

LeetCode 338 - Counting Bits Given an integer n, return an array ans of length n + 1 such that for each i (0 <= i <= n), ans[i] is the number of 1’s in the binary representation of i. example: Input: n = 2 Output: [0,1,1] Explanation: 0 --> 0 1 --> 1 2 --> 10 Input: n = 5 Output: [0,1,1,2,1,2] Explanation: 0 --> 0 1 --> 1