: first-row ( n -- t )
[ <failure> <success> <failure> ] dip
- 1- [| a b c | b c <block> a b ] times 2drop ;
+ 1 - [| a b c | b c <block> a b ] times 2drop ;
GENERIC: total ( t -- n )
M: block total [ total ] dup choice + ;
M: end total ways>> ;
: solve ( width height -- ways )
- [ first-row ] dip 1- [ next-row ] times total ;
+ [ first-row ] dip 1 - [ next-row ] times total ;
PRIVATE>