Problem 663. Crypto Addition - v01

Crypto addition is solving for the numeric values of the characters given in an addition equation:

   abc       756
  +def       342
  ----      ----
  ghij      1098

Input [ 'abc' , 'def' , 'ghij' ] Output [ 756 342 1098 ] or [ ] if no solution

All characters have unique values.

Leading zeros are not allowed.

This Crypto Addition v01 is limited to two addends and a sum.

The output is the number values [anum bnum cnum] given [astr, bstr,cstr].

If there is no solution the output should be [ ], empty set.

I am planning v02 thru v05 with additional complications.

v02 will have embedded numbers.

v03 will allow up to ten addends vs the current two.

A solid recursive routine can crack each test case in under 75 msec.