Description Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty […]

## Roman to Integer – #13 LeetCode

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 100 D 500 M 1000 For […]

## Palindrome Number – #9 LeetCode

Description Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: […]

## String to Integer (atoi) – #8 LeetCode

Description Implement atoi which converts a string to an integer. The function first discards as many whitespace characters as necessary until the first non-whitespace character is found. Then, […]

## Reverse Integer – #7 LeetCode

Description Given a 32-bit signed integer, reverse digits of an integer. Example 1: Input: 123 Output: 321 Example 2: Input: -123 Output: -321 Example 3: […]

## 3. Longest Substring Without Repeating Characters

Description Given a string, find the length of the longest substring without repeating characters. Example 1: Input: “abcabcbb” Output: 3 Explanation: The answer is “abc”, with the […]