IMHO solutions harcoding "NORTH" or "SOUTH" before "EAST" or "WEST" in the result.... should not pass ? Or I missed something in the description ?
Tests should include those ??

C++ translation someone ?

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)...