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543. Diameter of Binary Tree #Binary_Tree problem Given the root of a binary tree, return the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not
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387. First Unique Character in a String #hash_table problem Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1. Example 1: Input: s = "leetcode" Output: 0 Example 2: Input: s = "loveleetcode" Output: 2
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1207. Unique Number of Occurrences #Easy #Array #HashTable Problem URL problem Given an array of integers arr, return true if the number of occurrences of each value in the array is unique or false otherwise. Example 1: * Input: arr = [1,2,2,1,1,3] * Output: true * Explanation: The value
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2385. Amount of Time for Binary Tree to be Infected #Medium #BFS #DFS #Binary Tree problem You are given the root of a binary tree with unique values, and an integer start. At minute 0, an infection starts from the node with value start. Each minute, a node becomes infected
desing pattern
위 그림은 소프트웨어 아키텍처에서 Model-View-Controller (MVC) 패턴을 나타냅니다. MVC 패턴은 주로 웹 애플리케이션 개발에 사용되며, 애플리케이션의 구조를 세 가지 주요 구성 요소로 나눕니다: 모델(Model), 뷰(View), 컨트롤러(Controller). 1. 모델(Model): 데이터 레이어를 나타냅니다. 이는 애플리케이션의 데이터와 비즈니스 로직을 포함하며, 데이터베이스와의 상호작용을 관리합니다. 2. 뷰(View): 사용자 인터페이스(UI)
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Problem Consider all the leaves of a binary tree, from left to right order, the values of those leaves form a leaf value sequence. For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8). Two binary trees are considered leaf-similar if their leaf
java
LocalDate LocalDate (Java Platform SE 8 ) Java의 LocalDate 클래스는 날짜를 표현하기 위해 사용되는 클래스입니다. 이 클래스는 Java 8 이상에서 사용 가능한 java.time 패키지의 일부입니다. LocalDate는 시간대를 고려하지 않는 순수한 날짜(년, 월, 일)를 나타냅니다. 여기에는 시간, 분, 초 등의 시간 정보는 포함되어 있지 않습니다. java.time.LocalDate를 import하면
Problem 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]. Example 1: * Input: root = [10,5,15,3,7,null,18], low = 7, high = 15 * Output: 32
2870. Minimum number of Operations to make Array Empty #Medium #Hash #Quotient_remain You are given a 0-indexed array nums consisting of positive integers. There are two types of operations that you can apply on the array any number of times: Choose two elements with equal values and delete them
2125. Number of Laser Beams in a Bank # Medium # Array # Matrix Anti-theft security devices are activated inside a bank. You are given a 0-indexed binary string array bank representing the floor plan of the bank, which is an m x n 2D matrix. bank[i] represents the ith row, consisting
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1335. Minimum Difficulty of a Job Schedule #Hard Problem URL You want to schedule a list of jobs in d days. Jobs are dependent (i.e To work on the ith job, you have to finish all the jobs j where 0 <= j < i). You have to finish
1531. String Compression #Hard # Run-length encoding is a string compression method that works by replacing consecutive identical characters (repeated 2 or more times) with the concatenation of the character and the number marking the count of the characters (length of the run). For example, to compress the string "aabccc&