## Strings

beginner  concatenation

[Hello Name](/content/questions-base/exercise/hello-name/index.html)

intermediate  loops char case-insensitivity

[Count Vowels](/content/questions-base/exercise/count-vowels/index.html)

intermediate  HashMap loops substring sliding window

[Longest Substring No Char Repeat](/content/questions-base/exercise/longestSubstringNoCharRepeat/index.html)

## Arrays

beginner  if else operators index

[Is First Value 7](/content/questions-base/exercise/isFirstValue7/index.html)

## Conditionals

beginner  if else operators

[Is Number Even](/content/questions-base/exercise/isEven/index.html)

## Loops

beginner  while loops operators

[Sum Of Numbers](/content/questions-base/exercise/sumOfNumbers/index.html)