Have another suggestion (let you see): as I clicked several times before passing (waiting for the random tests NOT to generate such a case).. it means that invalid solutions may pass..

you should add such a case in the fixed tests. And may be in the first given tests.

I know why my first sol didn't pass (as well as ... why my accepted solution passes not 100% of the time)...
The condition for c to be less than int max in c++(in c++, use std::numeric_limits::max()) is never mentioned in the description....
Make a special description in

Trying C++, having a problem with random cases.

Failed for diff = 3514, low = 279314, high = 401782
Expected: equal to [  ]
Actual: [ [ 304696, 374643, 378157 ], [ 306740, 552471, 555985 ], [ 312230, 424864, 428378 ], [ 312258, 427352, 430866 ], [ 313234, 514216, 517730 ], [ 313262, 516712, 520226 ], [ 319362, 454680, 458194 ], [ 319684, 483959, 487473 ], [ 319864, 500339, 503853 ], [ 320186, 529664, 533178 ], [ 331446, 351440, 354954 ], [ 332700, 469943, 473457 ], [ 332952, 493811, 497325 ], [ 352814, 598504, 602018 ], [ 392798, 562616, 566130 ], [ 397434, 472768, 476282 ], [ 398438, 586464, 589978 ] ]

You can verify that the actual results are triples satisfying the requirements ;-)
How can the expected result be '[]' ??

??
Whenever encode or decode is called, my code prints in order input string and output string..
I Will check.

but... doesnt explain the output auab^... of the expected value ??

IMHO you should make the entry vector CONST... In a code lib you may not expect to change (sort) the vector input ??

Nice Kata.

If you have some trouble solving it... ask yourself why.. geometry tag was set... And be ready to draw and sketch (and scratch your head)...

I, as an amateur coder, found a lot of fun playing with pentomino problems..

So I just wanted to share!!

Thanks

brodiemark: see my 2::3 modifs.in approved kata... if you want python to 100% match C++.. would be easy to update...

Sorry, I think I get what you mean, but would you be more specific ? Describing one of the sample tests you think about ? Or provide with one ? Or ... simply help me on the way to GENERATE these falses grid (got no idea how to...)?

BTW... @nathan: saw your comments on the comments (!!!). I will (try to) fix, including the suggestion of dfwze on the occuring of the swapping of some letters. It's right to say that a wrong letter is MUCH EASIER to detect than a "wrong piece"...

If I may (don't know sh.. about python..): in C++, when using igloo and "Assert::That(...", it will abort at first error, am I right ?

@brodiemark and all: I will keep you posted with the upcoming modifications... But... the first beta version of the kata was 4 years ago... I'm now a grandpa (true) with less time to "codewars on" !!:-)