Array Repetition: Efficient Query Resolution for Dynamic Expansion Operations
Problem Overview
Given an empty array a, perform n operations of two types:
Type 1: Append a number x (1 ≤ x ≤ n) to the array.
Type 2: Replicate the current array x times (1 ≤ x ≤ 10^9) and append the copies.
After all operations, q queries ask for the value at position k (1-indexed). Constraints: n, q ≤ 10^5, and 1 ≤ k ≤ min(10^18, final_ar ...
Posted on Wed, 03 Jun 2026 18:12:25 +0000 by mastercjb
Range Queries with Mo's Algorithm and Block Decomposition
Problem Statement
Given a sequence of length n: S1, S2, S3, ..., Sn, process T queries. Each query provides four integers l, r, a, b. For all indices i ∈ [l, r], answer two questions:
Count of positions where Si ∈ [a, b]
Number of distinct values among Si that satisfy Si ∈ [a, b]
Constraints: n ≤ 10^5, T ≤ 10^6
Analysis of Failed Approaches
A ...
Posted on Wed, 03 Jun 2026 18:04:59 +0000 by saraadmin
In-Place Removal of Specific Array Values
The objective is to modify an integer array by removing all instances of a specific value directly within the original memory space. The function must return the new length of the array after removal.
Constraints and Mechanics
The solution must adhere to strict space complexity requirements:
O(1) Extra Space: No additional arrays or data struc ...
Posted on Wed, 03 Jun 2026 17:23:48 +0000 by jordy
Data Structures Exam Questions and Solutions
Multiple Choice Questions
Computer algorithms refer to:
A. Calculation methods
B. Problem-solving steps
C. Sorting methods
D. Scheduling methods
Answer: B
Comparde to linked lists, sequential lists:
A. Allow easier random access
B. Have more scatterde physical storage
C. Enable simpler insertions/deletions
D. Better fit linear logical structur ...
Posted on Sat, 30 May 2026 22:33:26 +0000 by KefkaIIV
Segment Tree with Lazy Propagation in Java
A segment tree supports efficient range updates and queries over an array. The following implementation uses an explicit tree structure with lazy propagation.
Node Representation
Each node stores its interval boundaries, the aggregated sum, and a pending lazy value that needs to be propagated to its childran before any further traversal.
static ...
Posted on Sat, 30 May 2026 00:47:09 +0000 by bran
Linked List Fundamentals
A linked list is a linear data structure where elements, called nodes, are connected via pointers. Each node contains two parts: a data field and a pointer field that references the next node in the seqeunce. The last node's pointer is null, indicating the end of the list. The first node is known as the head.
Types of Linked Lists
Singly Linked ...
Posted on Tue, 26 May 2026 23:03:25 +0000 by jponte
Implementing and Analyzing Sequential Lists in Data Structures
Sequential List Operations
Sequential lists support fundamental operations including insertion, deletion, modification, and traversal. These operations form the basis for understanding more complex data structures.
Structure Definition
typedef int SLDataType;
typedef struct SeqList {
SLDataType* arr; // Storage array
int capacity; ...
Posted on Tue, 19 May 2026 18:50:17 +0000 by lional
Python Lists: A Complete Guide for Beginners
A list in Python is an ordered collection of elements enclosed in square brackets [ ]. Lists are mutable, meaning you can modify their contents after creation.
Accessing List Elements
To access elements in a list, use their index position starting from 0. Python lists are zero-indexed, so the first element is at index 0, the second at index 1, ...
Posted on Mon, 18 May 2026 09:48:52 +0000 by sineadyd
Link-Cut Trees: Dynamic Tree Data Structures
Link-Cut Trees (LCT) represent an advanced data structure specifically designed to handle dynamic tree problems efficient. By utilizing prefered path decomposition and Splay trees, LCT maintains and manipulates tree structures with logarithmic amortized time complexity for most operations.
Core Concepts
Preferred Path Decomposition
For a given ...
Posted on Mon, 18 May 2026 07:15:33 +0000 by ridiculous
Core Algorithmic Building Blocks for Competitive Programming
Mathematical Algorithms
Fast Exponentiation
Reduces the time complexity of computing powers to logarithmic time by leveraging binary decomposition of the exponent.
long long binary_pow(long long base, long long exp, long long mod) {
long long res = 1;
base %= mod;
while (exp > 0) {
if (exp & 1) res = (res * base) % mo ...
Posted on Sun, 17 May 2026 15:51:07 +0000 by TheMagician