Freaks City

Given a rectangular binary matrix representing a geographical map where character '1' indicates landmass and '0' represents water, the computational task is to enumerate distinct islands. An island forms when land cells connect horizontally or vertically; diagonal adjacency does not constitute valid connectivity. The grid periphery is assumed t ...

Reversing a Linnked List Problem: Given the head of a singly linked list, reverse the list and return the new head. Approach: Iterative Node Reversal To reverse a linked list iteratively, we can utilize three pointers: current, previous, and temporary. The current pointer traverses the list, while the previous pointer keeps track of the reverse ...

Given a string s, the objective is to locate and return longest substring that reads the same forwards and backwards. Examples Input: s = "babad" Output: "bab" Note: "aba" is also a valid answer. Input: s = "cbbd" Output: "bb" Input: s = "a" Output: "a" Input: s = "a ...

Given a m x n grid filled with non-negative numbers, find a path from the top-left corner to the bottom-right corner wich minimizes the sum of all numbers along its path. You can only move either down or right at any point in time. Approach: Dynamic Programming This problem is a classic example of dynamic porgramming. The key is to build a solu ...

1648. Sell Diminishing-Valued Colored Balls The objective is to maximize profit when selling balls whose values decrease by 1 after each sale. The optimal approach is a greedy strategy where we always sell the currently most valuable balls available. By sorting the inventory in descending order, we can visualize the stock as columns. We process ...

Binary search is a fundamental algorithm that efficiently locates target values in sorted arrays. This article explores several classic LeetCode problems that leverage binary search, along with related array manipulation techniques. Problem 704: Binary Search When performing binary search on a sorted array, the choice of boundary conditions sig ...

203. Remove Linked List Elements This problem requires removing all nodes from a singly linked list that have a specific value. Two common approaches demonstrate key linked list operation patterns: using the original head node directly, and using a dummy head node to unify handling of all nodes. Aproach 1: Without Dummy Head When operating with ...

Hash Table Algorithms: Solving Multi-Sum Problems 4Sum II (LeetCode 454) Problem Description Given four integer arrays nums1, nums2, nums3, and nums4, all of length n, return the number of tuples (i, j, k, l) such that: 0 <= i, j, k, l < n nums1[i] + nums2[j] + nums3[k] + nums4[l] == 0 Example 1: Input: nums1 = [1,2], nums2 = [-2,-1 ...

The objective is to identify two numbers within an integer array that sum up to a specific target value and return their indices. It is assumed that there is exactly one valid solution per input and that an element cannot be used twice. For example, given the array nums = [2, 7, 11, 15] and target = 9, the function should return [0, 1] becuase ...

Find the Champion in an Array Game Given a distinct-integer array arr and an integer k, simulate a game where the first two elements compete in each round. The larger value wins, stays at index 0, and the smaller one is moved to the end. The game ends as soon as any value wins k consecutive rounds; that value is the champion. Examples arr = [2 ...