PROBLEM DESCRIPTION Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C ...

PROBLEM DESCRIPTION Given a roman numeral, convert it to an integer. leetcode SOLUTION APPROACH 1 If there are two characters left in the string s AND the integer value of first roman characte...

PROBLEM DESCRIPTION Given an array of integers citations where citations[i] is the number of citations a researcher received for their ith paper, return the researcher’s h-index. According to the...

PROBLEM DESCRIPTION You are given an integer array prices where prices[i] is the price of a given stock on the ith day. On each day, you may decide to buy and/or sell the stock. You can only hold...

DESIGN PATTERNS Creational Design Patterns Singleton: A pattern that ensures a class has only one instance. Builder: A pattern to cons...

OBSERVER The Observer design pattern is a behavioral design pattern that establishes a one-to-many dependency between objects, so that when one object changes its state, all the dependent objects ...

PROBLEM DESCRIPTION Given an integer array nums sorted in non-decreasing order, remove some duplicates in-place such that each unique element appears at most twice. The relative order of the eleme...

STRATEGY The Strategy design is a behavioral design pattern that allows us to define different strategies (or ways) to solve a problem and switch between them easily. It helps us encapsulate each ...

PROBLEM DESCRIPTION You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively....

FLYWEIGHT The Flyweight pattern is a design pattern that helps optimize memory usage by sharing common data between multiple objects. It is particularly useful when dealing with objects that have ...