## 11. Integer to Roman

Problem Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. For example, 2 is written as II in Roman numeral, just two one’s added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II. Roman numerals are usually written largest to smallest from left to right. However, Read more…

## 11. Container With Most Water

Problem You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]). Find two lines that together with the x-axis form a container, such that the container contains the most water. Return the maximum amount of water a container can store. Read more…

## 10. Regular Expression Matching

Problem Given an input string s and a pattern p, implement regular expression matching with support for ‘.’ and ‘*’ where: ‘.’ Matches any single character.​​​​ ‘*’ Matches zero or more of the preceding element. The matching should cover the entire input string (not partial). Problem description Given an input string s and a pattern p, we need to implement a Read more…

## 9. Palindrome Number

Problem Description Given an integer x, return true if x is a palindrome, and false otherwise. Given an integer x, the task is to determine if it is a palindrome. A palindrome is a number that remains the same when its digits are reversed. For example, 121 is a palindrome, but 123 is not. Solution The solution to Read more…

## 8. String to Integer (atoi)

Problem description Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer (similar to C/C++’s atoi function). The algorithm for myAtoi(string s) is as follows: Read in and ignore any leading whitespace. Check if the next character (if not already at the end of the string) is ‘-‘ or ‘+’. Read this character in if Read more…

## 7. Reverse Integer

Problem description Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 – 1], then return 0. Assume the environment does not allow you to store 64-bit integers (signed or unsigned). Solution Given a signed 32-bit integer x, the Read more…

## 6. Zigzag Conversion

Problem Description The Zigzag Conversion problem involves converting a given string into a zigzag pattern with a specified number of rows. The pattern is read line by line, and the result should be the concatenation of each line. For example, the string “PAYPALISHIRING” with 3 rows would result in “PAHNAPLSIIGYIR”. Read more…

## 3. Longest Substring Without Repeating Characters

Problem Description Given a string s, find the length of the longestsubstring without repeating characters. In computer science, a string is a sequence of characters, and a substring is a contiguous sequence of characters within a string. Given a string s, the task of finding the length of the longest substring without repeating Read more…

## 1. Two Sums Problem

Problem Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order. Solution This problem is known as the Read more…