[LeetCode] 148. Sort List - 문제풀이 Description 주어진 링크드리스트를 오름자순으로 정렬하여 반환하는 문제입니다. Example 1: Input: head = [4,2,1,3] Output: [1,2,3,4] Example 2: Input: head = [-1,5,3,4,0] Output: [-1,0,3,4,5] Example 3: Input: head = [] Output: [] Constraints: The number of nodes in the list is in the range [0, 5 * 10^4]. -10^5 알고리즘/LeetCode 2022. 2. 24. 14:31
[LeetCode] 133. Clone Graph - 문제풀이 Description 연결된 무방향 그래프에서 노드의 참조가 주어집니다. 그래프의 전체 복사본(클론)을 반환합니다. 그래프의 각 노드에는 인접 노드의 값(int)과 목록(List[Node])이 포함됩니다. Given a reference of a node in a connected undirected graph. Return a deep copy (clone) of the graph. Each node in the graph contains a value (int) and a list (List[Node]) of its neighbors. class Node { public int val; public List neighbors; } Test case format: For simplicity, each .. 알고리즘/LeetCode 2022. 2. 23. 12:07
[LeetCode] 171. Excel Sheet Column Number - 문제풀이 Description Excel 시트에 나타나는 열 제목을 나타내는 문자열 columnTitle이 지정된 경우 해당 열 번호를 반환합니다. Given a string columnTitle that represents the column title as appear in an Excel sheet, return its corresponding column number. For example: A -> 1 B -> 2 C -> 3 ... Z -> 26 AA -> 27 AB -> 28 ... Example 1: Input: columnTitle = "A" Output: 1 Example 2: Input: columnTitle = "AB" Output: 28 Example 3: Input: columnTitle.. 알고리즘/LeetCode 2022. 2. 22. 13:14
[LeetCode] 169. Majority Element - 문제풀이 Description nums크기 의 배열이 주어지면 다수 요소n 를 반환 합니다 . 과반수 요소는 여러 번 나타나는 요소입니다 . 다수 요소가 항상 배열에 존재한다고 가정합니다. Given an array nums of size n, return the majority element. The majority element is the element that appears more than ⌊n / 2⌋ times. You may assume that the majority element always exists in the array. Example 1: Input: nums = [3,2,3] Output: 3 Example 2: Input: nums = [2,2,1,1,1,2,2] Output: 2 .. 알고리즘/LeetCode 2022. 2. 21. 11:23
[LeetCode] 1288. Remove Covered Intervals - 문제풀이 Description 간격을 나타내는 배열 intervals이 주어지면 목록의 다른 간격에 포함된 모든 간격을 제거합니다.intervals[i] = [li, ri][li, ri) 간격 [a, b)은 및 인 경우에만 간격에 포함 [c, d)됩니다 .c 알고리즘/LeetCode 2022. 2. 20. 19:18
[LeetCode] 402. Remove K Digits - 문제풀이 Description 주어진 정수에서 k자리수 만큼 제거했을때 가능한 가장 작은 값을 반환하는 문제입니다. Given string num representing a non-negative integer num, and an integer k, return the smallest possible integer after removing k digits from num. Example 1: Input: num = "1432219", k = 3 Output: "1219" Explanation: Remove the three digits 4, 3, and 2 to form the new number 1219 which is the smallest. Example 2: Input: num = "10200", k .. 알고리즘/LeetCode 2022. 2. 18. 18:55
[LeetCode] 39. Combination Sum - 문제풀이 Description 주어진 배열에서 중복이 허용되는 조합의 합이 target이 되는 모든 요소를 반환하는 문제입니다. 요소의 값이 같고 순서가 다른 것은 동일한 조합으로 칩니다. 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 .. 알고리즘/LeetCode 2022. 2. 17. 12:15
[LeetCode] 485. Max Consecutive Ones - 문제풀이 Description 주어진 배열에서 최대로 연속되는 1의 개수를 구하는 문제입니다. Given a binary array nums, return the maximum number of consecutive 1's in the array. Example 1: Input: nums = [1,1,0,1,1,1] Output: 3 Explanation: The first two digits or the last three digits are consecutive 1s. The maximum number of consecutive 1s is 3. Example 2: Input: nums = [1,0,1,1,0,1] Output: 2 Constraints: 1 알고리즘/LeetCode 2022. 2. 17. 00:51
[LeetCode] 24. Swap Nodes in Pairs - 문제풀이 Description 인접한 두개의 노드끼리 swap하여 반환하는 문제입니다. Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i.e., only nodes themselves may be changed.) Example 1: Input: head = [1,2,3,4] Output: [2,1,4,3] Example 2: Input: head = [] Output: [] Example 3: Input: head = [1] Output: [1] Constraints: The number of .. 알고리즘/LeetCode 2022. 2. 16. 11:13
[LeetCode] 136. Single Number - 문제풀이 Description 비어있지 않은 배열이 주어지고 하나의 원소만 한개의 값을 가지고 나머지는 2개씩 값을 가지고있을때 하나의 원소 반환하는 문제입니다. Given a non-empty array of integers nums, every element appears twice except for one. Find that single one. You must implement a solution with a linear runtime complexity and use only constant extra space. Example 1: Input: nums = [2,2,1] Output: 1 Example 2: Input: nums = [4,1,2,1,2] Output: 4 Example 3: Input.. 알고리즘/LeetCode 2022. 2. 15. 02:49
[LeetCode] 190. Reverse Bits - 문제풀이 Description 주어진 부호없는 32비트 정수를 뒤집어서 반환하는 문제입니다. Reverse bits of a given 32 bits unsigned integer. Note: Note that in some languages, such as Java, there is no unsigned integer type. In this case, both input and output will be given as a signed integer type. They should not affect your implementation, as the integer's internal binary representation is the same, whether it is signed or unsigned. In.. 알고리즘/LeetCode 2022. 2. 15. 02:09
[LeetCode] 191. Number of 1 Bits - 문제풀이 Description 주어진 정수의 bit(1)의 개수를 반환하는 문제입니다. Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). Note: Note that in some languages, such as Java, there is no unsigned integer type. In this case, the input will be given as a signed integer type. It should not affect your implementation, as the integer's internal binary repre.. 알고리즘/LeetCode 2022. 2. 15. 01:31
[LeetCode] 231. Power of Two - 문제풀이 Description 주어진수가 2의 제곱에 포함되는지 여부를 반환하는 문제입니다. Given an integer n, return true if it is a power of two. Otherwise, return false. An integer n is a power of two, if there exists an integer x such that n == 2x. Example 1: Input: n = 1 Output: true Explanation:2^0 = 1 Example 2: Input: n = 16 Output: true Explanation:2^4 = 16 Example 3: Input: n = 3 Output: false Constraints: -2^31 0010000 n-1 > 11.. 알고리즘/LeetCode 2022. 2. 14. 23:52
[LeetCode] 235. Lowest Common Ancestor of a Binary Search Tree - 문제풀이 Description 이진검색트리에서 주어진 두 노드의 가장 최하위 공통 조상 LCA를 찾아 반환하는 문제입니다. Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. 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).” E.. 알고리즘/LeetCode 2022. 2. 14. 17:47
[LeetCode] 653. Two Sum IV - Input is a BST - 문제풀이 Description 주어진 유효한 이진검색트리에서 두개의 요소의 합이 k가 되는 경우가 있는지 여부를 반환하는 문제입니다. Given the root of a Binary Search Tree and a target number k, return true if there exist two elements in the BST such that their sum is equal to the given target. Example 1: Input: root = [5,3,6,2,4,null,7], k = 9 Output: true Example 2: Input: root = [5,3,6,2,4,null,7], k = 28 Output: false Constraints: The number of nodes in.. 알고리즘/LeetCode 2022. 2. 14. 14:23
[Leetcode] 98. Validate Binary Search Tree - 문제풀이 Description 주어진 이진트리가 유효한 이진탐색트리인지 여부를 반환하는 문제입니다. Given the root of a binary tree, determine if it is a valid binary search tree (BST). A valid BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with keys greater than the node's key. Both the left and right subtrees must also be binary sea.. 알고리즘/LeetCode 2022. 2. 14. 13:45
[LeetCode] 701. Insert into a Binary Search Tree - 문제풀이 Description 주어진 이진 검색 트리에서 특정 값을 올바른 노드에 삽입 후 root를 반환하는 문제입니다. You are given the root node of a binary search tree (BST) and a value to insert into the tree. Return the root node of the BST after the insertion. It is guaranteed that the new value does not exist in the original BST. Notice that there may exist multiple valid ways for the insertion, as long as the tree remains a BST after inserti.. 알고리즘/LeetCode 2022. 2. 14. 13:12
[LeetCode] 700. Search in a Binary Search Tree - 문제풀이 Description 주어진 이진검색트리(BST)에서 val와 같은 값을 가지는 노드를 반환하는 문제입니다. You are given the root of a binary search tree (BST) and an integer val. Find the node in the BST that the node's value equals val and return the subtree rooted with that node. If such a node does not exist, return null. Example 1: Input: root = [4,2,7,1,3], val = 2 Output: [2,1,3] Example 2: Input: root = [4,2,7,1,3], val = 5 Output: .. 알고리즘/LeetCode 2022. 2. 14. 02:40
[LeetCode ] 112. Path Sum - 문제풀이 Description 주어진 이진트리를 root부터 leaf 노드까지 탐색하여 targetSum과 일치하는 값이 있는지 찾아가는 문제입니다. Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum. A leaf is a node with no children. Example 1: Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22 Output: true Explanation: T.. 알고리즘/LeetCode 2022. 2. 14. 02:02
[LeetCode] 226. Invert Binary Tree - 문제풀이 Description 주어진 이진 트리를같은 뎁스의 값들을 뒤집어(invert) 반환하는 문제입니다. Given the root of a binary tree, invert the tree, and return its root. Example 1: Input: root = [4,2,7,1,3,6,9] Output: [4,7,2,9,6,3,1] Example 2: Input: root = [2,1,3] Output: [2,3,1] Example 3: Input: root = [] Output: [] Constraints: The number of nodes in the tree is in the range [0, 100]. -100 알고리즘/LeetCode 2022. 2. 14. 01:23
