[LeetCode] 103. Binary Tree Zigzag Level Order Traversal

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given the root of a binary tree, return the zigzag level order traversal of its nodes' values. (i.e., from left to right, then right to left for the next level and alternate between). Example 1: Input: root = [3,9,20,null,null,15,7] Output: [[3],[20,9],[15,7]] Example 2: Input: root = [1] Output: [[1]] Example 3: Input: root = [] Output: [] Constraints: The n..
Algorithm/LeetCode 2023. 7. 20. 04:05
[LeetCode] 22. Generate Parentheses

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Example 1: Input: n = 3 Output: ["((()))","(()())","(())()","()(())","()()()"] Example 2: Input: n = 1 Output: ["()"] Constraints: 1 0) { backtrack(result, s + "(", left - 1, right); } if (right > 0) { backtrack(result, s + ")", left, right - 1); } } } back..
Algorithm/LeetCode 2023. 7. 19. 00:48
[LeetCode] 150. Evaluate Reverse Polish Notation

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem You are given an array of strings tokens that represents an arithmetic expression in a Reverse Polish Notation. Evaluate the expression. Return an integer that represents the value of the expression. Note that: The valid operators are '+', '-', '*', and '/'. Each operand may be an integer or another expression. The division between two integers always truncat..
Algorithm/LeetCode 2023. 7. 18. 00:50
[LeetCode] 380. Insert Delete GetRandom O(1)

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Implement the RandomizedSet class: RandomizedSet() Initializes the RandomizedSet object. bool insert(int val) Inserts an item val into the set if not present. Returns true if the item was not present, false otherwise. bool remove(int val) Removes an item val from the set if present. Returns true if the item was present, false otherwise. int getRandom() Return..
Algorithm/LeetCode 2023. 7. 17. 02:29
[LeetCode] 238. Product of Array Except Self

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. You must write an algorithm that runs in O(n) time and without using the division operation. Example 1: Input: nums = [1,2,3,4] Output:..
Algorithm/LeetCode 2023. 7. 16. 01:17
[LeetCode] 34. Find First and Last Position of Element in Sorted Array

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value. If target is not found in the array, return [-1, -1]. You must write an algorithm with O(log n) runtime complexity. Example 1: Input: nums = [5,7,7,8,8,10], target = 8 Output: [3,4] Example 2: Input: nums = [5,7,7,8,8,10], target = 6 ..
Algorithm/LeetCode 2023. 7. 15. 23:54
[LeetCode] 236. Lowest Common Ancestor of a Binary Tree

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself).” Example 1: Input: root = [3,5,1,6,2,0,8,..
Algorithm/LeetCode 2023. 7. 14. 01:27
[LeetCode] 207. Course Schedule

소스 코드는 여기 있습니다. 문제는 여기 있습니다. 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 bi first if you want to take course ai. For example, the pair [0, 1], indicates that to take course 0 you have to first take course 1. Return true if you can fini..
Algorithm/LeetCode 2023. 7. 13. 00:32
[LeetCode] 139. Word Break

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given a string s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words. Note that the same word in the dictionary may be reused multiple times in the segmentation. Example 1: Input: s = "leetcode", wordDict = ["leet","code"] Output: true Explanation: Return true because "leetcod..
Algorithm/LeetCode 2023. 7. 12. 00:27
[LeetCode] 3. Longest Substring Without Repeating Characters

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given a string s, find the length of the longest substring without repeating characters. Example 1: Input: s = "abcabcbb" Output: 3 Explanation: The answer is "abc", with the length of 3. Example 2: Input: s = "bbbbb" Output: 1 Explanation: The answer is "b", with the length of 1. Example 3: Input: s = "pwwkew" Output: 3 Explanation: The answer is "wke", with..
Algorithm/LeetCode 2023. 7. 11. 00:36
[LeetCode] 49. Group Anagrams

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given an array of strings strs, group the anagrams together. You can return the answer in any order. An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once. Example 1: Input: strs = ["eat","tea","tan","ate","nat","bat"] Output: [["bat"],["nat","tan"],["ate","eat","t..
Algorithm/LeetCode 2023. 7. 10. 03:37
[LeetCode] 1143. Longest Common Subsequence

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0. A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters. For example, "ace" is a subsequence of "a..
Algorithm/LeetCode 2023. 7. 9. 03:00
[LeetCode] 105. Construct Binary Tree from Preorder and Inorder Traversal

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given two integer arrays preorder and inorder where preorder is the preorder traversal of a binary tree and inorder is the inorder traversal of the same tree, construct and return the binary tree. Example 1: Input: preorder = [3,9,20,15,7], inorder = [9,3,15,20,7] Output: [3,9,20,null,null,15,7] Example 2: Input: preorder = [-1], inorder = [-1] Output: [-1] C..
Algorithm/LeetCode 2023. 7. 8. 01:49
[LeetCode] 45. Jump Game II

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem You are given a 0-indexed array of integers nums of length n. You are initially positioned at nums[0]. Each element nums[i] represents the maximum length of a forward jump from index i. In other words, if you are at nums[i], you can jump to any nums[i + j] where: 0
Algorithm/LeetCode 2023. 7. 7. 04:31
[LeetCode] 199. Binary Tree Right Side View

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given the root of a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. Example 1: Input: root = [1,2,3,null,5,null,4] Output: [1,3,4] Example 2: Input: root = [1,null,3] Output: [1,3] Example 3: Input: root = [] Output: [] Constraints: The number of nodes in the tree is in the..
Algorithm/LeetCode 2023. 7. 6. 03:31
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