Chris Wen's Blog

DescriptionGiven an integer x, return true if x is a palindrome, and false otherwise. Example 1:123Input: x = 121Output: trueExplanation: 121 reads as 121 from left to right and from right to left.Example 2:123Input: x = -121Output: falseExplanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.Example 3:123Input: x = 10Output: falseExplanation: Reads 01 from right to left. Therefore it is not a palindrome. 123Constraints:-231 <= ...

ReferencesDive Into Deep Learning Create Environmentuse conda or miniconda123conda env remove d2l-zhconda create -n d2l-zh -y python=3.8 pipconda activate d2l-zh install dependencies1pip install jupyter d2l torch torchvision download d2l-zh.zip123wget http://zh-v2.d2l.ai/d2l-zh.zipunzip d2l-zh.zipjupyter notebook

DescriptionGiven a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-2^31, 2^31 - 1], then return 0. Example 1: 12Input: x = 123Output: 321 Example 2: 12Input: x = -123Output: -321 Example 3: 12Input: x = 120Output: 21 Example 4: 12Input: x = 0Output: 0 Constraints: -2^31 <= x <= 2^31 - 1 Approach1234567891011121314151617class Solution: def reverse(self, x: int) -> int: sign = -1 if ...

DescriptionImplement the myAtoi(string s) function, which converts a string to a 32-bit signed integer. The algorithm for myAtoi(string s) is as follows: Whitespace: Ignore any leading whitespace (“ “). Signedness: Determine the sign by checking if the next character is ‘-‘ or ‘+’, assuming positivity if neither present. Conversion: Read the integer by skipping leading zeros until a non-digit character is encountered or the end of the string is reached. If no digits were read, then the resul...

DescriptionYou are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]). Find two lines that together with the x-axis form a container, such that the container contains the most water. Return the maximum amount of water a container can store. Notice that you may not slant the container. Example 1:123Input: height = [1,8,6,2,5,4,8,3,7]Output: 49Explanation: The above vertical lines are represented ...

Large Language ModelDefinitionA large language model is a machine learning model that is trained on a large corpus of text data, such as Wikipedia or the Web. These models can generate high-quality text that is similar to the training data, but can also generate text that is not present in the training data. History < 1990s: IBM’s statistical language model (SLM) 1990s-2000s: Neural language models (NLLMs) 2001s: n-gram model 2010s: GPT-2, GPT-3 Dataset PreprocessingTokenizationSplitting ...

DescriptionThe string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility) 123P A H NA P L S I I GY I R Write the code to convert a string to a zigzag pattern. You should do it in-place. Example 1: 12Input: s = "PAYPALISHIRING", numRows = 3Output: "PAHNAPLSIIGYIR" Example 2: 1234567Input: s = "PAYPALISHIRING", numRows = 4Output: "...

DescriptionGiven a string s, return the longest palindromic substring in s. Example 1:123Input: s = "babad"Output: "bab"Explanation: "aba" is also a valid answer.Example 2:12Input: s = "cbbd"Output: "bb"1234Constraints:1 <= s.length <= 1000s consist of only digits and English letters. Approach: Expand Around Center1234567891011121314151617181920212223class Solution: def longestPalindrome(self, s: str) -> str: if not s or len...

GraphA graph is a data structure that consists of a set of nodes (also called vertices) and a set of edges that connect pairs of nodes. Graphs can be directed or undirected, depending on whether the edges have a direction associated with them. They are used to represent various types of relationships and connections, such as social networks, transportation systems, and communication networks. Types of Graphs Directed Graph (Digraph): A graph where each edge has a direction, indicating a one-w...

DescriptionGiven two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). Example 1:123Input: nums1 = [1,3], nums2 = [2]Output: 2.00000Explanation: merged array = [1,2,3] and median is 2.Example 2:123Input: nums1 = [1,2], nums2 = [3,4]Output: 2.50000Explanation: merged array = [1,2,3,4] and median is (2 + 3) / 2 = 2.5. 12345678Constraints:nums1.length == mnums2.length == n0 <= m <=...