The Minimum Size Subarray Sum problem asks us to find the smallest contiguous subarray whose sum is greater than or equal to a given integer target. If no such subarray exists, we return 0. This problem is common in array manipulation and sliding window techniques. In simple terms, imagine you’re…

Imagine you are looking at a family tree. If you flip it horizontally, the left children become right children and the right children become left children. This is exactly what the Invert Binary Tree problem asks us to do: swap all the left and right children of every node in…

The Linked List Cycle II problem asks you to determine where a cycle begins in a linked list if one exists. A cycle occurs when a node in the list points back to a previous node, creating a loop. The task involves returning the starting node of the cycle or…

This problem asks you to design and implement your own linked list from scratch, either as a singly linked list or a doubly linked list, depending on your choice. Here’s a simplified explanation of the requirements: Tradeoffs Between Singly and Doubly Linked List 1. Singly Linked List: • Simpler to…

Linked lists are one of the most foundational data structures in computer science, and rearranging them can be a fun yet challenging task. One such problem is Reorder List, where you’re required to rearrange the elements of a singly linked list into a specific order. Let’s break this problem into…

The “Word Search” problem challenges you to determine if a word exists in a grid of letters. The word can be constructed by sequentially adjacent cells in the grid, where “adjacent” means horizontally or vertically neighboring. Each cell in the grid can be used only once per word. Imagine this…

The “Length of Last Word” problem asks us to find the length of the last word in a given string. A word is defined as a maximal substring consisting only of non-space characters. The problem may involve handling edge cases like multiple trailing spaces or no words at all. It…

The Binary Tree Right Side View problem asks us to return the nodes that are visible when a binary tree is viewed from its right side. Imagine standing to the right of a tree and looking at it: you can only see the rightmost nodes of each level. This problem…

Constructing a binary tree from its preorder and inorder traversals involves rebuilding the tree using the order in which nodes are visited. Preorder traversal visits the root node first, followed by the left and right subtrees, while inorder traversal visits the left subtree, root, and then the right subtree. By…

You are given a list of daily temperatures. For each day, you need to figure out how many days you must wait until the temperature becomes warmer. If there’s no future day with a warmer temperature, just put 0 for that day. The result will be a new list showing…