Word numbers: Billion approaches (2008)(conway.rutgers.edu)
conway.rutgers.edu
Word numbers: Billion approaches (2008)
http://conway.rutgers.edu/~ccshan/wiki/blog/posts/WordNumbers1/
4 comments
> If the integers from 1 to 999,999,999 are written as words, sorted alphabetically, and concatenated, what is the 51 billionth letter?
Are we supposed to include spaces in this concatenated string?
Are we supposed to include spaces in this concatenated string?
The code in the linked article doesn't add spaces between words, so probably not.
I specifically remember this problem from ITA's advertisements on the MBTA.
In a series of posts, mathematician Dylan Thurston and computer scientist / linguist Chung-chieh Shan solve this problem step by step, introducing concepts such as monoids and differentiation along the way, use the programming language Haskell.
Epilogue: Discussion with a representative from ITA Software, the creators of the problem: http://conway.rutgers.edu/~ccshan/wiki/blog/posts/WordNumber...