[LeetCode] 155. Min Stack

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Design 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 minimu..
Algorithm/LeetCode 2023. 7. 22. 04:06
[LeetCode] 300. Longest Increasing Subsequence

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given an integer array nums, return the length of the longest strictly increasing subsequence. Example 1: Input: nums = [10,9,2,5,3,7,101,18] Output: 4 Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4. Example 2: Input: nums = [0,1,0,3,2,3] Output: 4 Example 3: Input: nums = [7,7,7,7,7,7,7] Output: 1 Constraints: 1
Algorithm/LeetCode 2023. 7. 21. 04:46
[LeetCode] 103. Binary Tree Zigzag Level Order Traversal

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given the root of a binary tree, return the zigzag level order traversal of its nodes' values. (i.e., from left to right, then right to left for the next level and alternate between). Example 1: Input: root = [3,9,20,null,null,15,7] Output: [[3],[20,9],[15,7]] Example 2: Input: root = [1] Output: [[1]] Example 3: Input: root = [] Output: [] Constraints: The n..
Algorithm/LeetCode 2023. 7. 20. 04:05
[LeetCode] 22. Generate Parentheses

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem 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 0) { backtrack(result, s + "(", left - 1, right); } if (right > 0) { backtrack(result, s + ")", left, right - 1); } } } back..
Algorithm/LeetCode 2023. 7. 19. 00:48
[LeetCode] 150. Evaluate Reverse Polish Notation

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem You 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 truncat..
Algorithm/LeetCode 2023. 7. 18. 00:50
[LeetCode] 380. Insert Delete GetRandom O(1)

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Implement the RandomizedSet class: RandomizedSet() Initializes the RandomizedSet object. bool insert(int val) Inserts an item val into the set if not present. Returns true if the item was not present, false otherwise. bool remove(int val) Removes an item val from the set if present. Returns true if the item was present, false otherwise. int getRandom() Return..
Algorithm/LeetCode 2023. 7. 17. 02:29
[LeetCode] 238. Product of Array Except Self

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. You must write an algorithm that runs in O(n) time and without using the division operation. Example 1: Input: nums = [1,2,3,4] Output:..
Algorithm/LeetCode 2023. 7. 16. 01:17
[LeetCode] 34. Find First and Last Position of Element in Sorted Array

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value. If target is not found in the array, return [-1, -1]. You must write an algorithm with O(log n) runtime complexity. Example 1: Input: nums = [5,7,7,8,8,10], target = 8 Output: [3,4] Example 2: Input: nums = [5,7,7,8,8,10], target = 6 ..
Algorithm/LeetCode 2023. 7. 15. 23:54
[LeetCode] 236. Lowest Common Ancestor of a Binary Tree

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself).” Example 1: Input: root = [3,5,1,6,2,0,8,..
Algorithm/LeetCode 2023. 7. 14. 01:27
[LeetCode] 207. Course Schedule

소스 코드는 여기 있습니다. 문제는 여기 있습니다. Problem There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, bi] indicates that you must take course bi first if you want to take course ai. For example, the pair [0, 1], indicates that to take course 0 you have to first take course 1. Return true if you can fini..
Algorithm/LeetCode 2023. 7. 13. 00:32
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