꿈꾸는공학도

Linked list의 loop이 있는지 확인하는 건 1칸 씩 이동하는 slow와 2칸 씩 이동하는 Fast를 선언해서 T/F를 반환할 수 있었다고 알고 있었는데, 전체 list의 길이를 반환하는 거는 처음봤다. 일차적으로 내가 풀었을 땐 # Do not modify!class LinkedNode: def __init__(self, value): self.value = value self.next = None def hasLoop(head): if not head : return 0, True if not head.next : return 1,True slow = head fast = head.next cond = False while fast and f..

https://leetcode.com/problems/symmetric-tree/description/Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center). Example 1:Input: root = [1,2,2,3,4,4,3]Output: trueExample 2:Input: root = [1,2,2,null,3,null,3]Output: false Constraints:The number of nodes in the tree is in the range [1, 1000].-100  Follow up: Could you solve it both recursively..

https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree/Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on.Return the smallest level x such that the sum of all the values of nodes at level x is maximal. Example 1:Input: root = [1,7,0,7,-8,null,null]Output: 2Explanation: Level 1 sum = 1.Level 2 sum = 7 + 0 = 7.Level 3 sum = 7 + -8 = -1...

https://leetcode.com/problems/binary-tree-inorder-traversal/description/Given the root of a binary tree, return the inorder traversal of its nodes' values. Example 1:Input: root = [1,null,2,3]Output: [1,3,2]Example 2:Input: root = []Output: []Example 3:Input: root = [1]Output: [1] Constraints:The number of nodes in the tree is in the range [0, 100].-100 굉장히 기초적인 것이라고 생각했던 부분들인데 모르겠다아 짜증난다.. 1. P..

https://leetcode.com/problems/length-of-last-word/description/Given a string s consisting of words and spaces, return the length of the last word in the string.A word is a maximal substring consisting of non-space characters only. Example 1:Input: s = "Hello World"Output: 5Explanation: The last word is "World" with length 5.Example 2:Input: s = " fly me to the moon "Output: 4Explanation: ..

https://leetcode.com/problems/merge-sorted-array/description/You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.Merge nums1 and nums2 into a single array sorted in non-decreasing order.The final sorted array should not be returned by the function, but instead be stored ins..

https://leetcode.com/problems/search-insert-position/description/Given a sorted array of distinct integers and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You must write an algorithm with O(log n) runtime complexity. Example 1:Input: nums = [1,3,5,6], target = 5Output: 2Example 2:Input: nums = [1,3,5,6], target ..

https://leetcode.com/problems/convert-1d-array-into-2d-array/description/You are given a 0-indexed 1-dimensional (1D) integer array original, and two integers, m and n. You are tasked with creating a 2-dimensional (2D) array with  m rows and n columns using all the elements from original.The elements from indices 0 to n - 1 (inclusive) of original should form the first row of the constructed 2D ..

https://leetcode.com/problems/adding-spaces-to-a-string/description/You are given a 0-indexed string s and a 0-indexed integer array spaces that describes the indices in the original string where spaces will be added. Each space should be inserted before the character at the given index.For example, given s = "EnjoyYourCoffee" and spaces = [5, 9], we place spaces before 'Y' and 'C', which are at..

https://leetcode.com/problems/reverse-linked-list/description/Given the head of a singly linked list, reverse the list, and return the reversed list. Example 1:Input: head = [1,2,3,4,5]Output: [5,4,3,2,1]Example 2:Input: head = [1,2]Output: [2,1]Example 3:Input: head = []Output: [] Constraints:The number of nodes in the list is the range [0, 5000].-5000 Follow up: A linked list can be reversed e..