문제Given the root of a binary tree, return an array of the largest value in each row of the tree (0-indexed). Example 1:Input: root = [1,3,2,5,3,null,9] Output: [1,3,9] Example 2:Input: root = [1,2,3] Output: [1,3]  Constraints:The number of nodes in the tree will be in the range [0, 104].-231 풀이 bfs를 사용하는 문제이다.각 row를 bfs 로 찾고, for loop안의 각 element의 최댓값을 찾아준다.코드/** * Definition for a binary tree ..

문제Given a string s, reverse only all the vowels in the string and return it.The vowels are 'a', 'e', 'i', 'o', and 'u', and they can appear in both lower and upper cases, more than once. Example 1:Input: s = "IceCreAm"Output: "AceCreIm"Explanation:The vowels in s are ['I', 'e', 'e', 'A']. On reversing the vowels, s becomes "AceCreIm".Example 2:Input: s = "leetcode"Output: "leotcede" Constraints:..

문제Given an integer array nums, handle multiple queries of the following types:Update the value of an element in nums.Calculate the sum of the elements of nums between indices left and right inclusive where left Implement the NumArray class:NumArray(int[] nums) Initializes the object with the integer array nums.void update(int index, int val) Updates the value of nums[index] to be val.int sumRang..

문제Given an array arr of 4 digits, find the latest 24-hour time that can be made using each digit exactly once.24-hour times are formatted as "HH:MM", where HH is between 00 and 23, and MM is between 00 and 59. The earliest 24-hour time is 00:00, and the latest is 23:59.Return the latest 24-hour time in "HH:MM" format. If no valid time can be made, return an empty string. Example 1:Input: arr = [..