💡 Problem Formulation: Wildcard matching is commonly used in search operations where you want to match strings with patterns containing wildcard characters. For instance, if you want “*.txt” to match any files that end with “.txt“, the wildcard “*” stands for any sequence of characters. This article demonstrates how to accomplish wildcard matching in Python, … Read more
💡 Problem Formulation: The ‘trapping rain water’ problem involves calculating the total amount of rainwater that can be trapped within a given set of non-negative integer arrays, which represent elevation maps. Each element in the array corresponds to the elevation at that position. For example, given the input array [0,1,0,2,1,0,1,3,2,1,2,1], the desired output is 6 … Read more
💡 Problem Formulation: The problem is to identify the smallest positive integer that does not appear in a given sequence of numbers. For instance, given an input [3, 4, -1, 1], the desired output is 2, because it is the smallest positive integer missing from the list. Method 1: Sorting and Linear Scan This method … Read more
💡 Problem Formulation: Given a string containing just the characters ‘(‘ and ‘)‘, the goal is to find the length of the longest well-formed (valid) parentheses substring. For example, given the input ‘()()‘, the desired output is ‘4‘, whereas for ‘(())‘, the output should also be ‘4‘. Method 1: Stack-Based Approach The Stack-Based Approach involves … Read more
💡 Problem Formulation: Imagine you have multiple sorted lists, and your goal is to combine them into a single sorted list. For example, if your input is [[10, 20], [30], [40, 50, 60]], the desired output would be [10, 20, 30, 40, 50, 60]. This article walks through different methods to achieve that in Python. … Read more
💡 Problem Formulation: Regular expressions are a powerful tool for pattern matching and text manipulation. In Python, they are widely used for parsing strings, checking for the presence of specific patterns, and extracting substrates. This article discusses how to perform regular expression matching in Python, with an example input of “example.email+json@gmail.com” and the desired output … Read more
💡 Problem Formulation: In Python, it’s common to encounter a situation where you have a dictionary represented as a string and you need to convert it back into a usable dictionary object. For example, you might have the string dictionary “{‘key’: ‘value’, ‘number’: 42}” and want to convert it to a Python dictionary object {‘key’: … Read more
💡 Problem Formulation: When programming in Python, there may be times when you need to convert a set into a list. Sets are unordered collections of unique elements while lists are ordered collections of elements which can have duplicates. For example, you may begin with a set {‘apple’, ‘banana’, ‘cherry’} and want to convert it … Read more
💡 Problem Formulation: In Python programming, it’s common to have a scenario where you need to take a single multi-digit number and break it down into its constituent digits as a list of integers. For instance, converting the integer 12345 to the list [1, 2, 3, 4, 5]. Method 1: Using ‘map’ and ‘int’ One … Read more
💡 Problem Formulation: Python developers often need to convert a list of tuples into a list of strings for easier manipulation and display. An example scenario could involve converting a list like [(‘John’, ‘Doe’), (‘Jane’, ‘Smith’)] into a list of strings like [‘John Doe’, ‘Jane Smith’]. This article explores five effective methods to perform this … Read more
💡 Problem Formulation: When working with data structures in Python, it’s common to encounter a scenario where you have a list of tuples, but the requirements of your program necessitate a list of lists instead. For example, you might start with [(1, 2), (3, 4), (5, 6)] and need to convert it to [[1, 2], … Read more
💡 Problem Formulation: The ‘maximum path sum’ in a binary tree is the greatest sum of node values that can be obtained by traversing a path from any node to any other node, where each node can only be used once in the path. The binary tree nodes have a ‘value’, and two children ‘left’ … Read more