1. Problem Summary You are given an array heights, where each element represents the height of a bar in a histogram.All bars have a width of exactly 1. Your task is to compute the area of the largest rectangle that can be formed within the histogram, where: Example interpretation:If: The largest rectangle has area: So…

1. Problem Summary You are given: Rules: Your task is to compute the minimum number of boats required to rescue everyone. Example interpretation:If: Possible grouping: Total boats: 2. Key Insights 1. Greedy pairing strategy works To minimize boats, we should try pairing the lightest with the heaviest person. 2. Sorting enables two-pointer optimization After sorting:…

1. Problem Summary You are given the head of a sorted singly linked list.Your task is to remove all nodes that have duplicate values, meaning: Return the head of the updated list containing only distinct values. Example interpretation:Input: Values 3 and 4 appear more than once, so remove them entirely. Output: 2. Key Insights Sorted…

1. Problem Summary You are given the heads of two singly linked lists, list1 and list2. Both linked lists are: Your task is to merge the two lists into a single sorted linked list and return the head of the merged list. Important details: Example interpretation:If the lists are: Merged result becomes: 2. Key Insights…

1. Problem Summary You are given an integer n, and you must count how many permutations of numbers 1 through n satisfy the following condition: For every position i (1-based index): These permutations are called Beautiful Arrangements. Your task is to return the total number of such valid permutations. Example interpretation:If n = 2, the…

1. Problem Summary You are given: Your task is to: Return the node in the cloned tree that corresponds to the target node in the original tree. Important details: The output must be a reference to the matching node in the cloned tree. 2. Key Insights Value comparison is not reliable Because multiple nodes can…

1. Problem Summary You are given: Your task is to determine whether arr can be formed by concatenating the arrays in pieces in any order, with these rules: Return: Example interpretation:Input: We can concatenate [85] + [1,2] to form [85,1,2] → return true. 2. Key Insights Each subarray in pieces must match starting from some…

1. Problem Summary You are given an integer array nums that: You are also given an integer target. Your task is to determine whether target exists in the array.Return: Example interpretation:If nums = [2,5,6,0,0,1,2] and target = 0, the answer is true.If target = 3, the answer is false. 2. Key Insights This problem differs…

1. Problem Summary You are given an encoded string s that follows a specific pattern, and your task is to decode it. The encoding rules are: Where: Example interpretation:Input: Decoding steps: Final output: 2. Key Insights Nested encodings require a stack-based solution You cannot decode from left to right in a single pass without remembering…

1. Problem Summary You are given an array of intervals, where each interval is represented as: Your task is to: Important details: Example:Input: Output: Because [1,3] and [2,6] overlap and merge into [1,6]. 2. Key Insights 1. Sorting by start time is crucial If intervals are sorted by their start value: 2. When do intervals…