LeetCode No. Problem Name Difficulty Solutions 1 Two Sum Easy .Net Code 3 Longest Substring Without Repeating Characters Medium .Net Code 7 Reverse Integer Easy .Net Code 9 Palindrome Number Easy .Net Code 13 Roman to Integer Easy .Net Code 14 Longest Common Prefix Easy .Net Code 20 Valid Parentheses Easy .Net Code 43 Multiply Strings Medium .Net Code 53 Maximum Subarray Easy .Net Code 58 Length of Last Word Easy .Net Code 66 Plus One Easy .Net Code 217 Contains Duplicate Easy .Net Code 219 Contains Duplicate II Easy .Net Code 220 Contains Duplicate III Easy .Net Code 283 Move Zeroes Easy .Net Code 344 Reverse String Easy .Net Code 415 Add Strings Easy .Net Code 560 Subarray Sum Equals K Meduim .Net Code 771 Jewels and Stones Easy .Net Code 989 Add to Array-Form of Integer Easy .Net Code 1108 Defanging an IP Address Easy .Net Code 1281 Subtract the Product and Sum of Digits of an Integer Easy .Net Code 1295 Find Numbers with Even Number of Digits Easy .Net Code 1313 Decompress Run-Length Encoded List Easy .Net Code