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TIL/알고리즘 연습

 (5)
[LeetCode] 136. Single Number, 191. Number of 1 Bits 136. Single Number링크https://leetcode.com/problems/single-number/description/ 풀이시간 - 10:39var singleNumber = function(nums) { const map ={} for (let i=0; i# answervar singleNumber = function(nums) { let uniqNum = 0; for (let idx = 0; idx   인사이트베타적 논리합 잊고 있었고, 써본 적도 없었는데 이런식으로 활용할 수 있구나하고 놀랐다.191. Number of 1 Bits 링크https://leetcode.com/problems/single-number/description/ 풀이시간 - 07:27v..
[Leetcode] 202. Happy Number, 350. Intersection of Two Arrays II 202. Happy Number링크https://leetcode.com/problems/happy-number/description/풀이시간 - 11:29function sumDigits(num) { let sum = 0 let numStr = num.toString() for (let i =0; ivar calculateSquare = function(num) { let sum = 0; while (num > 0) { let digit = num % 10; sum += digit * digit; num = Math.floor(num / 10); } return sum;};var isHappy = function(n) { l..
[Leetcode] 268. Missing Number, 412. Fizz Buzz, 344. Reverse String, 242. Valid Anagram, 387. First Unique Character in a String 268. Missing Number링크https://leetcode.com/problems/missing-number/description/ 풀이시간 - 5:25var missingNumber = function(nums) { for (let i=0; i# 리팩토링 코드 O(n^2) => O(n)var missingNumber = function(nums) { const arr = Array.from({length :nums.length+1}).fill(-1) for (let i=0; i x === -1)};인사이트1. 내장함수는 적절하게 사용해야한다. 무지성으로 사용하니 O(n^2)으로 늘어났다.412. Fizz Buzz(2:17),344. Reverse String(11:44),242..
[Leetcode] 20. Valid Parentheses , 69. Sqrt(x), 66. Plus One 20. Valid Parentheses링크https://leetcode.com/problems/valid-parentheses/description/  풀이시간 - 26:00function checkParent(char) { if (char === '(') return 's' if (char === ')') return 'sc' if (char === '{') return 'm' if (char === '}') return 'mc' if (char === '[') return 'l' if (char === ']') return 'lc'}var isValid = function(s) { let stack = [] for (let i =0; i# 리팩토리 코드var..
[Leetcode] 1. Two Sum, 13. Roman to Integer 1. Two Sum링크https://leetcode.com/problems/two-sum/ 풀이시간 - 5:05var twoSum = function(nums, target) { for (let i=0; i 인사이트없음 13. Roman to Integer링크https://leetcode.com/problems/roman-to-integer/description/ 풀이시간 - 52:03const ROMAN_NUMBER = { I: 1, V: 5, X: 10, L: 50, C: 100, D: 500, M: 1000,};const SPECIAL_CASES = { 'I': { 'V': true, 'X': true }, 'X': { 'L': true, 'C': true }, 'C': { ..

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