꿈꾸는공학도

https://leetcode.com/problems/minimum-length-of-string-after-operations/description/?envType=daily-question&envId=2025-01-13You are given a string s.You can perform the following process on s any number of times:Choose an index i in the string such that there is at least one character to the left of index i that is equal to s[i], and at least one character to the right that is also equal to s[i]..

https://leetcode.com/problems/word-subsets/description/?envType=daily-question&envId=2025-01-10You are given two string arrays words1 and words2.A string b is a subset of string a if every letter in b occurs in a including multiplicity.For example, "wrr" is a subset of "warrior" but is not a subset of "world".A string a from words1 is universal if for every string b in words2, b is a subset of a..

https://leetcode.com/problems/lru-cache/description/DBMS Buffer에 Data를 Replace 하는 대표적인 Algorithm 중 하나인 LRU 방법에 대해 Implementation을 해보는 실습을 해본다. 문제 Description은 아래와 같다.Design a data structure that follows the constraints of a Least Recently Used (LRU) cache.Implement the LRUCache class:LRUCache(int capacity) Initialize the LRU cache with positive size capacity.int get(int key) Return the value of ..

사실 Palindrome 문제는 유형도 많고, DP를 이용해서 풀면 편하지만 너~무 짜친다. 아오 하기 싫어! Longest Palindrome Substring(이하 LPS) 문제를 2개 풀게 됐는데, 하나는 10초컷 / 하나는 30분을 고민해도 어렵다.. 쉬운 문제는 아래와 같다.def is_palindromic(s: str) -> bool: """ > input 's' - A string consisting of only lowercase English letters (1 return a boolean """ # WRITE YOUR CODE HERE n = len(s) left = 0 right = n-1 while left  그냥 input에 대해..

https://leetcode.com/problems/unique-binary-search-trees/description/Given an integer n, return the number of structurally unique BST's (binary search trees) which has exactly n nodes of unique values from 1 to n. Example 1:Input: n = 3Output: 5Example 2:Input: n = 1Output: 1 Constraints:1 그래도 가볍게나마 BST문제도 풀어봐야지..! Linked List , Tree 이런 걸 자꾸만 건들자 근데 이건,, Tree 문제라기보단 수학 문제 같다.. 흐음..  1. Python 일단..

https://leetcode.com/problems/minimum-number-of-operations-to-move-all-balls-to-each-box/description/?envType=daily-question&envId=2025-01-06You have n boxes. You are given a binary string boxes of length n, where boxes[i] is '0' if the ith box is empty, and '1' if it contains one ball.In one operation, you can move one ball from a box to an adjacent box. Box i is adjacent to box j if abs(i - j)..

https://leetcode.com/problems/number-of-ways-to-split-array/description/?envType=daily-question&envId=2025-01-03You are given a 0-indexed integer array nums of length n.nums contains a valid split at index i if the following are true:The sum of the first i + 1 elements is greater than or equal to the sum of the last n - i - 1 elements.There is at least one element to the right of i. That is, 0 R..

기본적으로 뭐,, 특별한 건 없다. 일단 Data base에 접근만 하면 우리가 흔히 아는 SQL문만 쭉쭉쭉 날리면 된다. Data를 조회, 정렬, Insert, Delete 다 할 수 있다.  예시는 PSQL 안에서 Vector DB관련 Element를 만드는 것이긴 한데, 뭐.. 일반 Data도 비슷한 맥락으로 가지고 놀 수 있다. 근데 중요한 건, DB 접속 전에 기본 PostgreSQL 상에서 써먹으면 유용한 Cheet들이 좀 있다. 1. PostgreSQL 서버 상태 확인 및 관리PostgreSQL 프로세스 확인 : ps aux | grep postgres --> 요 놈 은근 많이 쓰인다. 이런식으로 현재 postgres 라는 이름으로 Run 중인 프로세스를 확인한다.PostgreSQL 서비스 ..

https://leetcode.com/problems/count-vowel-strings-in-ranges/description/?envType=daily-question&envId=2025-01-02You are given a 0-indexed array of strings words and a 2D array of integers queries.Each query queries[i] = [li, ri] asks us to find the number of strings present in the range li to ri (both inclusive) of words that start and end with a vowel.Return an array ans of size queries.length,..

https://leetcode.com/problems/minimum-cost-for-tickets/description/?envType=daily-question&envId=2024-12-31You have planned some train traveling one year in advance. The days of the year in which you will travel are given as an integer array days. Each day is an integer from 1 to 365.Train tickets are sold in three different ways:a 1-day pass is sold for costs[0] dollars,a 7-day pass is sold for..