Sunday Times Teaser 2937 – Long Division
by Graham Smithers
Published January 6 2019 (link)
I wrote down a 2-digit number and a 5-digit number and then carried out a long division.
I then erased all of the digits in the calculation, other than the 1’s, and so finished up with the image above.
If I told you how many different digits I had erased, then you should be able to work out my two original numbers.
What were my two original numbers?
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This uses my partition_unique function that is described here
I realised Brian’s code could be adapted to give a Python dictionary solution, based on the answer having a unique number of digits
Here’s my solution using the [[ SubstitutedDivision() ]] and [[ filter_unique() ]] functions from the enigma.py library. [ https://www.magwag.plus.com/jim/enigma.html ]
[ https://repl.it/@jim_r/teaser2937 ]
Note that there are no further solutions to the more general problem where the erased digits may be 1.