Problem 1084. Square Digits Number Chain Terminal Value (Inspired by Project Euler Problem 92)
Solution Stats
Problem Comments
-
3 Comments
Let consider the case x=954
954 -> 122 -> 9 -> 81 -> 65 -> 61 -> 37 -> 58 -> 89 -> 145 -> 42 -> 20 -> 4 -> 16 -> 37
So 37 is seen twice, it should end up with 37, no ?
No, 89 shows up before 37 does
By the description at ProjectEuler.net, it seems M is correct in their statement. The description there reads: "continuously [...] form a new number until it [that number just formed] has been seen before." That is exactly what M has done. Project Euler says furthermore: "[...] EVERY starting number will eventually arrive at 1 or 89." That is _not_ the same as stating: "this number chain always terminates with either 1 or 89". The key difference is in "arrives at" (the number appears) versus "terminates with" (the number is the first to appear twice in the sequence). In M's example, the sequence truly 'terminates with' 37 (as M said), but before it terminates the sequence had 'arrived at' 89.
Solution Comments
-
1 Comment
This solution requires Neural Network Toolbox
Problem Recent Solvers199
Suggested Problems
-
Read a column of numbers and interpolate missing data
1865 Solvers
-
Project Euler: Problem 1, Multiples of 3 and 5
2474 Solvers
-
Getting the indices from a matrix
568 Solvers
-
670 Solvers
-
643 Solvers
More from this Author56
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!