Strings No. Problem Difficulty 1 Add Strings Easy 2 Valid Anagram Easy 3 To Lower Case Easy 4 Shuffle String Easy 5 Check if Two String Arrays are Equivalent Easy 6 Merge Strings Alternately Easy 7 Length of Last Word Easy 8 Reverse Words in a String III Easy 9 Defanging an IP Address Easy 10 Find the Index of the First Occurrence Easy 11 Multiply Strings Medium 12 Shifting Letters Medium 13 Reverse Prefix of Word Easy 14 Number of Strings That Appear as Substrings in Word Easy 15 Detect Capital Easy 16 First Unique Character in a String Easy 17 Jewels and Stones Easy 18 First Letter to Appear Twice Easy 19 Count the Number of Special Characters I Easy 20 Longest Substring Without Repeating Characters Medium 21 Greatest Common Divisor of Strings Easy 22 Rotate String Easy 23 Capitalize the Title Easy 24 Find the Difference Easy 25 Number of Segments in a String Easy 26 Sort Vowels in a String Medium 27 Reverse Vowels of a String Easy 28 Minimize String Length Medium 29 Score of a String Medium 30 Reverse String Easy 31 Determine if String Halves Are Alike Easy 32 Find First Palindromic String in the Array Easy 33 Find Words Containing Character Medium 34 Is Subsequence Easy 35 Longest Palindrome Easy 36 Valid Word Medium 37 Replace Words Medium 38 Add-binary Easy 39 Fizz-buzz Easy 40 Valid-palindrome Easy 41 Second-largest-digit-in-a-string Easy 42 Remove-digit-from-number-to-maximize-result Easy 43 Check-if-string-is-a-prefix-of-array Easy 44 Check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence Easy