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문제 설명Given head, the head of a linked list, determine if the linked list has a cycle in it.There is a cycle in a linked list if there is some node in the list that can be reached again by continuously following the next pointer. Internally, pos is used to denote the index of the node that tail's next pointer is connected to. Note that pos is not passed as a parameter.Return true if there is a cy..

문제 설명Given a reference of a node in a connected undirected graph.Return a deep copy (clone) of the graph.Each node in the graph contains a value (int) and a list (List[Node]) of its neighbors.class Node { public int val; public List neighbors;}Test case format:For simplicity, each node's value is the same as the node's index (1-indexed). For example, the first node with val == 1, the secon..

문제 설명Given the root of a Binary Search Tree (BST), return the minimum absolute difference between the values of any two different nodes in the tree.Example 1:Input: root = [4,2,6,1,3]Output: 1Example 2:Input: root = [1,0,48,null,null,12,49]Output: 1Constraints:The number of nodes in the tree is in the range [2, 104].0 Note: This question is the same as 783: https://leetcode.com/problems/minimum-..

문제 설명You are given an array of strings tokens that represents an arithmetic expression in a Reverse Polish Notation.Evaluate the expression. Return an integer that represents the value of the expression.Note that:The valid operators are '+', '-', '*', and '/'.Each operand may be an integer or another expression.The division between two integers always truncates toward zero.There will not be any ..

문제 설명Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.Implement the MinStack class:MinStack() initializes the stack object.void push(int val) pushes the element val onto the stack.void pop() removes the element on the top of the stack.int top() gets the top element of the stack.int getMin() retrieves the minimum element in the stack.You must implem..

문제 설명Given an array of positive integers nums and a positive integer target, return the minimal length of asubarraywhose sum is greater than or equal to target. If there is no such subarray, return 0 instead.Example 1:Input: target = 7, nums = [2,3,1,2,4,3]Output: 2Explanation: The subarray [4,3] has the minimal length under the problem constraint.Example 2:Input: target = 4, nums = [1,4,4]Outpu..

[LeetCode Top Interview 150] 문제 설명Given a 1-indexed array of integers numbers that is already sorted in non-decreasing order, find two numbers such that they add up to a specific target number. Let these two numbers be numbers[index1] and numbers[index2] where 1 Return the indices of the two numbers, index1 and index2, added by one as an integer array [index1, index2] of length 2.The tests are g..

문제 설명A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.Given a string s, return true if it is a palindrome, or false otherwise.Example 1:Input: s = "A man, a plan, a canal: Panama"Output: trueExplanation: "amanaplanacan..