From charlesreid1

(Created page with "Cryptarithmetic example: https://developers.google.com/optimization/puzzles/cryptarithmetic <pre> CP + IS + FUN -------- = TRUE </pre> The challenge is to fin...")
 
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The challenge is to find integers to swap out for each letter such that the equation holds true. This is a constrained programming problem, and can be re-cast in terms of an arbitrary radix as follows:
The challenge is to find integers to swap out for each letter such that the equation holds true. This is a constrained programming problem, and can be re-cast in terms of an arbitrary radix as follows:


The "tens" place becomes the expression <math>\mbox{(C+I+F)}\times(\mbox{base})</math> on the left side and <math>\mbox{T}\times(\mbox{base})</math> on the right.
The "thousands" place has nothing on the left side, and a <math>\mbox{T}</math> on the right side.


The "ones" place becomes the expression <math>\mbox{P+S+N}</math> on the left and <math>\mbox{E}</math> on the right, which, combining, gives:
The "hundreds" place has an <math>F</math> on the left side and a <math>\mbox{R}</math> on the right side.
 
The "tens" place becomes the expression <math>(C+I+U) \times base</math> on the left side and <math>U \times base</math> on the right.
 
The "ones" place becomes the expression <math>P+S+N</math> on the left and <math>E</math> on the right, which, combining, gives:


<math>
<math>
\mbox{(C+I+F)}\times(\mbox{base}) + \mbox{P+S+N} = \mbox{T}\times(\mbox{base}) + \mbox{E}
F \times base^2 + (C+I+U) \times base + (P+S+N) = T \times base^3 + R \times base^2 + U \times base + E
</math>
</math>

Revision as of 08:11, 17 July 2017

Cryptarithmetic example: https://developers.google.com/optimization/puzzles/cryptarithmetic

      CP
+     IS
+    FUN
--------
=   TRUE

The challenge is to find integers to swap out for each letter such that the equation holds true. This is a constrained programming problem, and can be re-cast in terms of an arbitrary radix as follows:

The "thousands" place has nothing on the left side, and a $ \mbox{T} $ on the right side.

The "hundreds" place has an $ F $ on the left side and a $ \mbox{R} $ on the right side.

The "tens" place becomes the expression $ (C+I+U) \times base $ on the left side and $ U \times base $ on the right.

The "ones" place becomes the expression $ P+S+N $ on the left and $ E $ on the right, which, combining, gives:

$ F \times base^2 + (C+I+U) \times base + (P+S+N) = T \times base^3 + R \times base^2 + U \times base + E $