milliwonkim의 블로그

문제 Given an integer numRows, return the first numRows of Pascal's triangle. In Pascal's triangle, each number is the sum of the two numbers directly above it as shown: Example 1: Input: numRows = 5 Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]] Example 2: Input: numRows = 1 Output: [[1]] Constraints: 1

문제 You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money. Return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1. You may assume that you have an infinite number of each kind of coin. Example 1: Input: coins ..

문제 Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Example 1: Input: n = 3 Output: ["((()))","(()())","(())()","()(())","()()()"] Example 2: Input: n = 1 Output: ["()"] Constraints: 1 { if(n * 2 === s.length) { result.push(s) return; } if(l < n) dfs(s + '(', l + 1, r); if(r < l) dfs(s + ')', l, r + 1); } dfs('', 0, 0) return result; }

문제 Given a string s, return the longest palindromic substring in s. A string is called a palindrome string if the reverse of that string is the same as the original string. Example 1: Input: s = "babad" Output: "bab" Explanation: "aba" is also a valid answer. Example 2: Input: s = "cbbd" Output: "bb" Constraints: 1 = 0 && y < s.length && s[x] === s[y]) { x--; y++; } // 만약 x가 -1 일 때, 혹은 만약 y가 s.l..

문제 Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. A subarray is a contiguous part of an array. Example 1: Input: nums = [-2,1,-3,4,-1,2,1,-5,4] Output: 6 Explanation: [4,-1,2,1] has the largest sum = 6. Example 2: Input: nums = [1] Output: 1 Example 3: Input: nums = [5,4,-1,7,8] Output: 23 Constraints: 1

카데인의 알고리즘 각 수를 더했을 때 가장 큰수가 나오는 연속된 부분을 찾는 알고리즘(maxSubArray) const maxSubArray = nums => { let max = nums[0]; let current = Math.max(max, 0); for (let i = 1; i < nums.length; i += 1) { current += nums[i]; max = Math.max(max, current); current = Math.max(current, 0); } return max; };

문제 Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. Example 1: Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: The above elevation map (black section) is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped. Example 2: Inp..

문제 Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level). Example 1: Input: root = [3,9,20,null,null,15,7] Output: [[3],[9,20],[15,7]] Example 2: Input: root = [1] Output: [[1]] Example 3: Input: root = [] Output: [] Constraints: The number of nodes in the tree is in the range [0, 2000]. -1000

최대공약수와 최소공백수 최대공약수 // 유클리드 호제법 const gcd = (a, b) => { if(a % b === 0) { return b; } return gcd(b, a % b) }; // 반복문 const gcd = (a, b) => { // 큰 걸 작은 걸로 나누고 // 깔끔히 안나뉘었으면 // 작은걸 => 큰걸로 / 나눈나머지 => 작은걸로 다시 재조정해서 // 깔끔하게 나뉠 때 까지 반복 후 => 나머지가 없을 때 작은 값을 최대공약수로 한다 while(a % b !== 0) { [a, b] = [b, a % b] } return b; } 최대공배수 // 최소공배수 = (a * b) / 최대공약수 const gcd = (a, b) => { if(a % b === 0) { return b..

문제 Given an integer n, return the least number of perfect square numbers that sum to n. A perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself. For example, 1, 4, 9, and 16 are perfect squares while 3 and 11 are not. Example 1: Input: n = 12 Output: 3 Explanation: 12 = 4 + 4 + 4. Example 2: Input: n = 13 Output: 2 Explanatio..