Emily Rosemary Collins

💡 Problem Formulation: You need to calculate the sum of a range of sorted subarray sums. Given an array nums, we want to find the sum of all subarray sums sorted in non-decreasing order. For example, for an input array [1,2,3,4] and range [1,10], we want to calculate the sum of the first to the … Read more

💡 Problem Formulation: The task is to identify the smallest possible difference between the maximum and minimum values within an array after making up to three moves. Each move consists of either increasing or decreasing any element by 1. For example, given an input array [1, 5, 3, 2], the largest value is 5 and … Read more

💡 Problem Formulation: Given a binary string, the task is to write a Python program to find the total number of non-empty substrings that contain only the character ‘1’. For instance, if the input is ‘1101’, the desired output is 4 since the substrings with only 1s are ’11’, ‘1’, ‘1’, and ‘1’. Method 1: … Read more

💡 Problem Formulation: Imagine you are given a weighted graph where weights represent the probability of transitioning from one node to another. The challenge is to find the path between two nodes that has the maximum overall probability. This article will walk through five different methods to tackle this problem using Python. For instance, if … Read more

💡 Problem Formulation: In tree data structures, subtrees often represent hierarchical subsets of data. A common query might involve counting the nodes within a subtree that share a common label. For example, given a tree where each node is labelled with a letter, one might be tasked with finding the number of ‘A’-labelled nodes within … Read more

💡 Problem Formulation: In the context of array processing, a common task involves identifying subarrays whose elements sum to an odd number. Given an input array like [1, 2, 3, 4], we aim to find the count of all possible contiguous subarrays where the sum is odd. For this input, the desired output is 4, … Read more

💡 Problem Formulation: Given a string, the task is to compute the number of ‘good’ ways it can be split into two non-empty substrings, such that the number of distinct characters in both substrings is the same. For example, given the input “ababa”, a good split would result in strings “aba” and “ba” both containing … Read more

💡 Problem Formulation: Given two polynomials represented by linked lists, where each node contains the coefficient and the exponent, the objective is to add these polynomials to form a new polynomial that is also in the form of a linked list. For example, if the first polynomial is represented as 5x^2 + 4x + 3 … Read more

💡 Problem Formulation: Expression trees are tree data structures where the internal nodes represent operators and the leaf nodes represent operands. Such trees can be used to analyze and evaluate mathematical expressions. For instance, given an infix expression like (3 + 2) * 4, we want to build its expression tree and then evaluate the … Read more

💡 Problem Formulation: Finding the lowest common ancestor (LCA) in a binary tree involves locating the lowest node in the tree that has two given nodes as descendants. For example, given a binary tree and two node values, the function should return the LCA node value. For input nodes 4 and 5 in a binary … Read more

💡 Problem Formulation: In this article, we tackle the challenge of creating a duplicate structure of an n-ary tree in Python. Given a tree that consists of nodes with potentially multiple children, we aim to replicate its architecture to create a new instance with the same hierarchical order. This process is useful where tree-based data … Read more

💡 Problem Formulation: In the task of converting a binary string into an alternating binary string (where each digit is the opposite of its neighbor), our goal is to find the minimum number of changes needed. Given an input like 01010, no changes are needed as it is already alternating, but for 00011, at least … Read more