Freaks City

Definition A suffix automaton (SAM) for a string (s) is the minimal deterministic finite automaton (DFA) that accepts all suffixes of (s). Formally: A SAM is a directed acyclic graph (DAG) where nodes represent states and edges represent transitions. The source node (t_0) serves as the initial state. All states are reachable from (t_0). Each t ...

Remove Linked List Elements (LeetCode 203) Given the head of a linked list and an integer val, remove all nodes where Node.val == val and return the new head node. Using a dummy head simplifies handling edge cases, especially when the head node itself needs to be removed. A traversal pointer prev is used to point to the node preceding the one c ...

1. Binary Tree Categories Full Binary Tree: A binary tree where all nodes have either 0 or 2 children, and all leaf nodes are at the same level. For depth k, the tree contains (2^k - 1) nodes. Complete Binary Tree: A binary tree where all levels except possibly the last are completely filled, and all nodes are as far left as possible. Binary Se ...

Core Principles (Three Key Points) Underlying Structure HashMap uses an array as the primary storage, combined with linked lists for handling hash collisions, and converts to red-black trees when certain conditions are met. When a linked list exceeds 8 elements and the array length is at least 64, the structure transforms into a red-black tree, ...

Dictionaries A dictionary (dict) is a data structure that stores key-value pairs. Let's explore its pratcical usage. Creating Dictionaries Using the dict() constructor: person = dict(name="Alice", age=30, city="New York") print(person) # Output: {'name': 'Alice', 'age': 30, 'city': 'New York'} Using curly braces: person = ...

Convert Array to List with asList The Arrays.asList method wraps an array into a fixed-size list, enabling collection-based operations like iteration or passing to methods expecting a List. Signature: public static <T> List<T> asList(T... a) Example: import java.util.Arrays; import java.util.List; public class ArrayConversion { ...

Competition Overview The problem difficulty is generally estimated as F < A = J = I < L = G = E < C = K = H. The contest featured a mix of standard algorithms and optimization problems. Below is the detailed analysis and solution for each problem. Problem F: Prefix Sum Threshold Problem Statement:Given an initial score of 1500 and a sequence o ...

Stack and Queue in C++ STL The C++ Standard Library provides implementations of both stack and queue data structures. These are fundamental containers that follow specific access orders—LIFO (Last In, First Out) for stacks and FIFO (First In, First Out) for queues. Stack Interface push(element): Inserts an element at the top pop(): Removes the ...

Data Types and Internal Encodings Redis distinguishes between external data types exposed to users and internal encoding mechanisms that optimize memory usage. Understanding these mappings helps in capacity planning and performance tuning. String Implementation Strings utilize Simple Dynamic Strings (SDS) rather than raw C strings. SDS maintain ...

Tuple Indexing Tuples support both forward and reverse indexing: data = (10, 20, 30, 40, 50) print(data[0]) # Output: 10 print(data[-1]) # Output: 50 Nested tuples can be accessed using multiple indices: matrix = ((1, 2, 3), (4, 5, 6)) print(matrix[0][1]) # Output: 2 Iteration Iterate over sequences using while or for: values = (5, 10, 15 ...