Minor edit.

Author: John Washam

README.md

@@ -290,7 +290,7 @@ This is a shorter list than what I used. This is abbreviated to save you time.
 
 ### Interview Prep
 
-- [ ] [Programming Interviews Exposed: Coding Your Way Through the Interview, 4nd Edition](https://www.amazon.com/Programming-Interviews-Exposed-Through-Interview/dp/111941847X/)
+- [ ] [Programming Interviews Exposed: Coding Your Way Through the Interview, 4th Edition](https://www.amazon.com/Programming-Interviews-Exposed-Through-Interview/dp/111941847X/)
     - answers in C++ and Java
     - this is a good warm-up for Cracking the Coding Interview
     - not too difficult, most problems may be easier than what you'll see in an interview (from what I've read)