juliodcs-week86

1 files changed, 22 insertions, 17 deletions

diff --git a/challenge-086/juliodcs/raku/ch-2.raku b/challenge-086/juliodcs/raku/ch-2.raku
index 24d95396bc..ef6d7e99c7 100644
--- a/challenge-086/juliodcs/raku/ch-2.raku
+++ b/challenge-086/juliodcs/raku/ch-2.raku
@@ -18,12 +18,12 @@ sub solve-sudoku(@sudoku) {
         elsif $guess == 0 && $backtrack {

             # not valid guess and no more guesses to test

             # We give up with this position (we decrement index)

-            @sudoku[$y][$x] = 0;

+            @sudoku[$y;$x] = 0;

             $index--;

         }

         else {

             # valid guess (for now), increase index

-            @sudoku[$y][$x] = $guess;

+            @sudoku[$y;$x] = $guess;

             $backtrack = 0;

             $index++;

         }

@@ -36,14 +36,11 @@ sub solve-sudoku(@sudoku) {
 # so that we can speed up the process by processing first the boxes

 # that have less possible guesses

 sub get-indexes(@sudoku) {

-    @sudoku>>.list.flat Z ^81

+    eager @sudoku>>.list.flat Z ^81

         ==> map({ $^it.tail, count-guesses @sudoku, $^it.tail })

-        ==> grep *.tail > 0

-        ==> sort({ $^a.tail cmp $^b.tail })

+        ==> grep(*.tail > 0)

+        ==> sort(*.tail cmp *.tail)

         ==> map *.head

-        ==> my @indexes;

-

-    @indexes.list

 }

 

 # Translate index to (y, x) matrix positions

@@ -56,7 +53,7 @@ sub get-position($index) {
 sub count-guesses(@sudoku, $index) {

     my ($y, $x) := get-position $index;

 

-    @sudoku[$y][$x] > 0

+    @sudoku[$y;$x] > 0

         ?? 0

         !! elems get-guesses @sudoku, $y, $x, 0

 }

@@ -68,9 +65,17 @@ sub get-guesses(@sudoku, $y, $x, $last-guess) {
     my @square := get-square @sudoku, $y, $x;

     my @all-nums := (@cross-y, @cross-x, @square).flat.sort.unique.list;

 

-    (1 .. 9)

-        ==> grep({ 0 == elems @all-nums.grep: * == $^guess })

-        ==> grep * > $last-guess

+    # This 2 things puzzled me:

+    # 1)

+    #     `grep(-> $guess { 0 == elems @all-nums.grep: * == $guess })`

+    #     is almost twice as fast as:

+    #     `grep({ $_ == none @all-nums })`

+    #

+    # 2) Using `grep(* > $last-guess)` as the first grep, is VERY slow

+    

+    eager (1 .. 9)

+        ==> grep(-> $guess { 0 == elems @all-nums.grep: * == $guess })

+        ==> grep(* > $last-guess)

 }

 

 # For a (y,x) pair, it returns all the boxes of its inner square

@@ -78,17 +83,17 @@ sub get-square(@sudoku, $inner-y, $inner-x) {
     my $y := $inner-y - $inner-y % 3;

     my $x := $inner-x - $inner-x % 3;

 

-    @sudoku[$y+0][$x+0], @sudoku[$y+0][$x+1], @sudoku[$y+0][$x+2],

-    @sudoku[$y+1][$x+0], @sudoku[$y+1][$x+1], @sudoku[$y+1][$x+2],

-    @sudoku[$y+2][$x+0], @sudoku[$y+2][$x+1], @sudoku[$y+2][$x+2],

+    @sudoku[$y+0;$x+0], @sudoku[$y+0;$x+1], @sudoku[$y+0;$x+2],

+    @sudoku[$y+1;$x+0], @sudoku[$y+1;$x+1], @sudoku[$y+1;$x+2],

+    @sudoku[$y+2;$x+0], @sudoku[$y+2;$x+1], @sudoku[$y+2;$x+2]

 }

 

 # Makes some guess for a box.

 # If we are backtracking, we set a minimum value for the guess

 # (previous box value)

 sub make-guess(@sudoku, $y, $x, $backtrack) {

-    my $min-guess := $backtrack ?? @sudoku[$y][$x] !! 0;

-    my @guesses := get-guesses(@sudoku, $y, $x, $min-guess).list;

+    my $min-guess := $backtrack ?? @sudoku[$y;$x] !! 0;

+    my @guesses := get-guesses @sudoku, $y, $x, $min-guess;

 

     @guesses.elems == 0 ?? 0 !! @guesses.head

 }