1. forEach does not work on strings. Try to iterate through for loop

2. forEach does not allow break statement, Try to iterate through for loop

3. Object.keys() can either be O(n) or O(nlogn). Most cases it is O(n)

    4. Remember to return value from functions

    5. Always check for duplicates

    6. If array is sorted or not

    7. Can you sort the given array or not.