string

Overview

Challenges with std::string appunto

Special String Again

Solutions to Special String Again

• Solution1
  • Complexity: O(N) time and O(1) Space

String Reversing

Solutions to String Reverse Challenge at Hackerrank

• String Reverse1 and two problems are solved

1. The char by char string reversion

• It is simply solved with an O(N) loop from rbegin() to rend()

2. The word by word string reversion

• It is solved with a 2 step approach
  • First an O(N) char by char string reversion using the previous solution
  • Then an O(N) word explode, using getline() specifing the ' ' delimiter and reversing each specific word

Substring Find

• The Substring finding in 2 Strings on Hackerrank
• The goal is to check if 2 substrings has a common string but not to return the actual substring
• This makes the actual problem much easier than it seems as a necessary and sufficient condition is they share a char so the proposed solution1 focuses on solving this equivalent challenge
• It is implemented representing a string as an unordered_map of its chars (store O(1), loop O(N)) and then iterating over the other string looking up for each char in the other string (lookup O(1), loop O(N))