String Builder

String is immutable
String concatenation += is expensive

O(n)

Python | Java

String is immutable, meaning you can't change it once created. When you concatenate two strings, it doesn’t simply add one string at the end of another; it creates a new string (ouch). Use a StringBuilder instead (or string.join() on a list in Python), which essentially is a List<Character>.

· String += c → linear
· StringBuilder.append(c) → constant

LeetCode

1119. Remove Vowels from a String

Python | Java

• Relevant Problems

  https://leetcode.com/problems/remove-vowels-from-a-string/

  https://leetcode.com/problems/reverse-words-in-a-string/

  https://leetcode.com/problems/unique-email-addresses/

  https://leetcode.com/problems/repeated-dna-sequences/

  https://leetcode.com/problems/decode-string/

  https://leetcode.com/problems/custom-sort-string/

  https://leetcode.com/problems/add-strings/

  https://leetcode.com/problems/add-binary/

  https://leetcode.com/problems/largest-number/

  https://leetcode.com/problems/bold-words-in-string/

  https://leetcode.com/problems/add-bold-tag-in-string/