Strings Quiz

8 questions10 minPass: 60%+10 XP on first pass

Immutability, StringBuilder, palindromes, reversing words and expand-around-center.

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Question 1
Why is s = s + ch inside a loop slow in Java and Python?
Strings can only hold 255 charactersStrings are immutable, so each + copies the whole stringThe + operator is not defined for stringsIt isn't slow
Question 2
In Java, how should you compare the contents of two strings a and b?
a == ba.equals(b)a.compare(b)a = b

Question 3

What does this print?

s = "  the sky  is blue "
print(" ".join(reversed(s.split())))

Question 4
What does this print?
```
System.out.println('c' - 'a');
```
Question 5
How many centers does "expand around center" check for a string of length n?
n2n − 1n²n / 2
Question 6
What is the longest palindromic substring of "babad"? (either correct answer is accepted)
Question 7Select all that apply
Which techniques are commonly used for string problems? (select all that apply)
Two pointersCharacter counting (array of 26 or a hash map)Sliding windowDijkstra's algorithm
Question 8
What is the longest common prefix of ["flower", "flow", "flight"]?