내 맘대로 알고리즘/LeetCode 2020 May
May LeetCoding Challenge[Day6] - Majority Element
Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority element always exist in the array. Input: [3,2,3] Output: 3 Input: [2,2,1,1,1,2,2] Output: 2 1. 알고리즘을 해결하기 위해서 생각한 방법 - 해당 문제는 배열이 주어질 때, 주어진 배열의 크기 n보다, 항상 [n/2] 보다 많은 수가 존재한다. - 처음 접근 방법은 Map을 사용했다. Map을 통해서 K..
May LeetCoding Challenge[Day5] - First Unique Character in a String
Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Note: You may assume the string contain only lowercase letters. s = "leetcode" return 0. s = "loveleetcode" return 2. 1. 알고리즘을 해결하기 위해서 생각한 방법 - 해당 문제는 문자열이 입력으로 주어질 때, 특정 인덱스의 문자가 중복되지 않는 문자인 지 확인하는 문제이다. - 문자를 카운팅하고, 해당 문자열이 몇 개 존재하는 지 확인해야 한다. - 문자열을 카운팅하기 가장 쉬운 자료구조인 Map을 사용했고,..
May LeetCoding Challenge[Day4] - Number Complement
Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation. Input: 5 Output: 2 Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. 1. 알고리즘을 해결하기 위해서 생각한 방법 - 우선, 해당 문제는 5라는 값이 주어졌을 때, 이진 값으로 101이 되는데, 이 때 해당 값의 반대 되는 값을 return하면 된다. - 여기서, 해당 값의 반대 되는 값의 단어적 정의는 잘 모르겠고, complem..
May LeetCoding Challenge[Day3] - Ransom Note
Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false. Each letter in the magazine string can only be used once in your ransom note. Note:You may assume that both strings contain only lowercase letters. canConstruct("a", "..
May LeetCoding Challenge[Day2] - Jewels and Stones
You're given strings J representing the types of stones that are jewels, and S representing the stones you have. Each character in S is a type of stone you have. You want to know how many of the stones you have are also jewels. The letters in J are guaranteed distinct, and all characters in J and S are letters. Letters are case sensitive, so "a" is considered a different type of stone from "A". ..
May LeetCoding Challenge[Day1] - First Bad Version
You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the previous version, all the versions after a bad version are also bad. Suppose you have n versions [1, 2, ..., n] and you want to find out the first bad one, which causes all the following ones to be..