꿈꾸는공학도

C - 2개 / C++ - 2개 이렇게 총 4개의 코딩문제를 3시간에 거쳐서 풀어보았다. 문제는 Time / Space Complexcity를 크게 고려하지 않고, 정답만 도출되면 인정되는 부분이라 어거지로 코드를 짜서 답을 도출해내는 데에는 성공을 했으나.. 앞으로 좀 더 효율적인 코딩을 하기 위해선 Coding Review정도는 하고 넘어가는 것이 좋을 거 같아 글을 적어본다. 문제의 출처도 제공되진 않지만, 시험이 끝나고 내가 스스로 복기 + 구글링/GPT를 이용해서 문제 출처를 추려내어 보았다.  1번 문제https://school.programmers.co.kr/learn/courses/30/lessons/42627 프로그래머스SW개발자를 위한 평가, 교육, 채용까지 Total Solution을..

https://leetcode.com/problems/maximum-difference-between-node-and-ancestor/description/Given the root of a binary tree, find the maximum value v for which there exist different nodes a and b where v = |a.val - b.val| and a is an ancestor of b.A node a is an ancestor of b if either: any child of a is equal to b or any child of a is an ancestor of b. Example 1:Input: root = [8,3,10,1,6,null,14,nul..

https://leetcode.com/problems/sort-characters-by-frequency/description/Given a string s, sort it in decreasing order based on the frequency of the characters. The frequency of a character is the number of times it appears in the string.Return the sorted string. If there are multiple answers, return any of them. Example 1:Input: s = "tree"Output: "eert"Explanation: 'e' appears twice while 'r' and..

https://leetcode.com/problems/generate-parentheses/description/Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Example 1:Input: n = 3Output: ["((()))","(()())","(())()","()(())","()()()"]Example 2:Input: n = 1Output: ["()"] Constraints:1 간단한 Dynamic Programming 코딩 한 번 해보기!문제는 쉬워 보이나, 막상 코딩하려니까 좀 짜친다.  1. Python아래까지 풀다가 GG. 뭔가 뒤에 방법이 생각 안 난다..

https://leetcode.com/problems/stone-game-ix/description/Alice and Bob continue their games with stones. There is a row of n stones, and each stone has an associated value. You are given an integer array stones, where stones[i] is the value of the ith stone.Alice and Bob take turns, with Alice starting first. On each turn, the player may remove any stone from stones. The player who removes a ston..

https://leetcode.com/problems/find-minimum-in-rotated-sorted-array-ii/description/Suppose an array of length n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,4,4,5,6,7] might become:[4,5,6,7,0,1,4] if it was rotated 4 times.[0,1,4,4,5,6,7] if it was rotated 7 times.Notice that rotating an array [a[0], a[1], a[2], ..., a[n-1]] 1 time results in the ..

https://leetcode.com/problems/min-stack/description/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() removes the element on the top of the stack.int top() gets the top element of the stack.int getMin() retrieves t..

https://leetcode.com/problems/is-graph-bipartite/description/?envType=problem-list-v2&envId=graphThere is an undirected graph with n nodes, where each node is numbered between 0 and n - 1. You are given a 2D array graph, where graph[u] is an array of nodes that node u is adjacent to. More formally, for each v in graph[u], there is an undirected edge between node u and node v. The graph has the f..

https://leetcode.com/problems/find-if-path-exists-in-graph/description/?envType=problem-list-v2&envId=graphThere is a bi-directional graph with n vertices, where each vertex is labeled from 0 to n - 1 (inclusive). The edges in the graph are represented as a 2D integer array edges, where each edges[i] = [ui, vi] denotes a bi-directional edge between vertex ui and vertex vi. Every vertex pair is c..

https://leetcode.com/problems/design-circular-deque/사실 예전에 풀었던 문제인데, 다행히(?) 인간은 망각의 동물인지라 초면 인 것 마냥 풀었다. deque 구조의 delete / insert 등등의 method를 한번 구현해 보는 것이 골자! Design your implementation of the circular double-ended queue (deque).Implement the MyCircularDeque class:MyCircularDeque(int k) Initializes the deque with a maximum size of k.boolean insertFront() Adds an item at the front of Deque. Retu..