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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 ...

Algorithmic Complexity Fundamentals Algorithm performance is measured by execution duration and memory consumption. Time complexity quantifies the growth rate of operations relative to input size, while space complexity tracks auxiliary storage requirements. Engineers frequently accept higher memory usage to achieve faster runtimes. As input si ...

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 ...

Algorithm Overview Split: Use slow-fast pointer technique to locate the midpoint and partition the list into two halves. Recurse: Apply the same sorting procedure recursively on both halves. Merge: Combine the two sorted sublists into a single sorted list using a linear-time merge step. Implementation class ListNode { int value; ListN ...

Definition and Core Principles A Queue is a fundamental linear data structure that operates on the First-In-First-Out (FIFO) principle. Conceptually, it functions similarly to a real-world waiting line: entities enter from one end, known as the rear, and exit from the opposite end, known as the front. This strict ordering ensures that the eleme ...

Heap Data Structure Implementation Heaps are specialized tree-based data structures that satisfy the heap property. They are commonly used to implement priority queues and for efficient sorting algorithms. This article explores two practical applications of heaps: heap sort and sequence merging. Heap Sort Implemantation Heap sort is an efficien ...

Data Structure DefinitionThe FHQ Treap (Fredman, Hendler, and Zhou Treap) relies on a randomized heap priority to maintain balance without requiring complex tree rotations. Each node in the structure maintains essential metadata: pointers to left and right children, the node's value, a random priority weight, and the size of the subtree rooted ...

Minimum Size Subarray Sum Given an array of positive integers nums and a positive integer target, find the minimal length of a contiguous subarray whose sum is greater than or equal to target. If no such subarray exists, return 0. Examples: Input: target = 7, nums = [2,3,1,2,4,3]Output: 2Explanation: The subarray [4,3] has the minimal lengt ...

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 ...

Contest preparation requires a structured approach to covering fundamental algorithms and optimizing problem-solving strategies. The following outlines core technical topics and execution practices essential for competitive programming. Core Algorithms and Data Structures Simulation and Mathematics High-precision arithmetic is critical for p ...