Emily Rosemary Collins

💡 Problem Formulation: The task is to determine the smallest number of character swaps needed to convert one string into an anagram of another string. For instance, if the input strings are ‘aabc’ and ‘abca’, the minimum number of swaps required is 1—swap ‘b’ with the second ‘a’. The following methods explore efficient ways to … Read more

💡 Problem Formulation: In this article, we tackle the issue of transforming an “almost” Binary Search Tree (BST), in which just a few nodes violate the BST property, into an exact BST where every node adheres strictly to the BST rules. For example, given an input BST where two nodes’ values have been swapped by … Read more

💡 Problem Formulation: Imagine you are given an array where each element represents the cost at that position, and you are required to find the minimum cost to reach the last index starting from the first index. However, you may take at most k steps from your current position to advance. For example, with input … Read more

💡 Problem Formulation: Given a binary tree, we seek the length of the longest consecutive path, where consecutive refers to nodes with values subsequent to one another. For instance, in a binary tree with values (1, 2, 3, 4), a consecutive path could be 1-2-3. The challenge is to find and return the maximum length … Read more

💡 Problem Formulation: In combinatorial mathematics, a common problem is to find all subsets of a given set of integers whose sum is equal to a specific target number k. Given an array of positive integers, and a target value k, the task is to count the number of subsets whose sum equals k. For … Read more

💡 Problem Formulation: Given a matrix, we want to explore various methods to calculate the number of ways it can be divided into exactly k pieces. For instance, if we have a 2×3 matrix and want to cut it into k = 2 pieces, there are several ways to split it either horizontally or vertically. … Read more

💡 Problem Formulation: Calculating the largest rectangular area under a histogram is a common algorithmic problem where you are given a set of bars of different heights and need to find the area of the largest rectangle that fits entirely under the histogram. For instance, with an input histogram represented by the list of integers … Read more

💡 Problem Formulation: We need to determine the number of ways to choose empty cells from a given matrix in Python. For example, given the matrix where ‘X’ represents an occupied cell and ‘.’ represents an empty one, such as [[‘X’, ‘.’, ‘.’], [‘.’, ‘X’, ‘.’], [‘.’, ‘.’, ‘X’]], we want to find how many … Read more

💡 Problem Formulation: Determining whether a given point resides within or on the boundary of a polygon can be essential for geometric computations in Python. For instance, given a point with coordinates (x,y) and a polygon defined by a list of vertices [(x1,y1), (x2,y2), …, (xn,yn)], the objective is to develop a program that returns … Read more

💡 Problem Formulation: Finding the length of the longest circular increasing subsequence is a twist on the classic Longest Increasing Subsequence (LIS) problem. In this variant, the sequence is considered circular, meaning the end connects back to the beginning, potentially forming an increasing sequence that wraps around. For example, given the input array [2, 0, … Read more

💡 Problem Formulation: The task at hand involves determining whether a given string can be broken down into a sequence of words that are present within a specified list. For instance, if the input string is “applepie” and the list of words contains [“apple”, “pie”], the desired output should be True since “applepie” can be … Read more

💡 Problem Formulation: Python users often rely on built-in functions like eval() for evaluating mathematical expressions. However, sometimes, you may need to implement an expression evaluator without these conveniences—either for educational purposes or to satisfy certain constraints. For example, you might have the input string “3 + 2 * 2” and want to output the … Read more