MakerHyeon

https://leetcode.com/problems/valid-parentheses/ Valid Parentheses - LeetCode Valid Parentheses - Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: 1. Open brackets must be closed by the same type of brackets. 2. Open brackets must be leetcode.com 이 문제는 괄호의 짝이 맞는 지 확인후 맞다면 True,틀리다면 False를 Return하..

https://leetcode.com/problems/min-stack/ Min Stack - LeetCode Min Stack - Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. Implement the MinStack class: * MinStack() initializes the stack object. * void push(int val) pushes the element val onto the stack. * void pop() leetcode.com 이 문제의 핵심은 getMin이다. O(1)의 시간복잡도를 가지면서 Stack에서 최소값을 조회하려면 어떻게 해야할까? ..

https://leetcode.com/problems/valid-sudoku/description/ Valid Sudoku - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 조건1. 행중복X 조건2. 열중복X 조건3. 3X3 Group 에서 중복X 조건 1,2는 hash를 사용하여 쉽게해결가능하다.여기서 문제는 조건3이다. 3X3 Group의 중복체크를 어떻게 할 것인가? 이의 해결은 간단한 수학이다.0~8의 고정 스도쿠이며, 이를 3으로 나누면 몫은 0~2가 ..

https://leetcode.com/problems/group-anagrams/description/ Group Anagrams - LeetCode Group Anagrams - 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 e leetcode.com 주어 word들을 똑같은 알파벳들 가지고있는것끼리 묶어 반환하는문제, SOLUT..

https://leetcode.com/problems/baseball-game/description/ Baseball Game - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 주어진 리스트로 해당하는 연산을 해서 답을 구하는문제! SOLUTION CODE # PYTHON class Solution: def calPoints(self, operations: List[str]) -> int: i=0 num=len(operations) res=[] while i <..

https://leetcode.com/problems/concatenation-of-array/description/ Concatenation of Array - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 주어진 배열 nums의 길이X2만큼, 배열원소를 그대로 복사해서 늘려서 반환하는문제 Too easy! SOLUTION CODE # PYTHON class Solution(object): def getConcatenation(self, nums): """ :..

https://leetcode.com/problems/top-k-frequent-elements/ Top K Frequent Elements - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com ! 시간 복잡도는 O(nlogn) 이하여야 함 SOLUTION CODE # PYTHON ● Count 를 이용한 풀이 from collections import Counter class Solution: def topKFrequent(self, nums: List[int],..

https://leetcode.com/problems/two-sum/description/ Two Sum - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com SOLUTION CODE # PYTHON class Solution: def twoSum(self, nums: List[int], target: int) -> List[int]: for i in range(0,len(nums)): t = target - nums[i] for j in range(i+1,len(..