Merge pull request #1938 from fluca1978/pwc69

Pwc69

4 files changed, 83 insertions, 0 deletions

diff --git a/challenge-069/luca-ferrari/blog-1.txt b/challenge-069/luca-ferrari/blog-1.txt
new file mode 100644
index 0000000000..7eecad9c00
--- /dev/null
+++ b/challenge-069/luca-ferrari/blog-1.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2020/07/13/PerlWeeklyChallenge69.html#task1
diff --git a/challenge-069/luca-ferrari/blog-2.txt b/challenge-069/luca-ferrari/blog-2.txt
new file mode 100644
index 0000000000..27ef7197c5
--- /dev/null
+++ b/challenge-069/luca-ferrari/blog-2.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2020/07/13/PerlWeeklyChallenge69.html#task2
diff --git a/challenge-069/luca-ferrari/raku/ch-1.p6 b/challenge-069/luca-ferrari/raku/ch-1.p6
new file mode 100644
index 0000000000..018e9ce2e0
--- /dev/null
+++ b/challenge-069/luca-ferrari/raku/ch-1.p6
@@ -0,0 +1,50 @@
+#!raku
+
+
+
+
+
+sub MAIN( Int $A where { 1 <= $A <= 10**15 } = 1
+          , Int $B where { $A <= $B <= 10**15 } = 10**15 ) {
+    say "Working from $A to $B";
+
+    my %reverse = 0 => 0
+    , 1 => 1
+    , 6 => 9
+    , 8 => 8
+    , 9 => 6;
+
+
+    my @found = gather {
+        for $A .. $B {
+            # special case: single number
+            take $_  if $_.chars == 1 && $_ == any( 0, 1, 8 );
+
+            my @digits = $_.split: '', :skip-empty;
+
+            # special case: if the number of digits is odd
+            # the central digit must be a self reversing one
+            next if ! @digits.elems %% 2
+            &&  @digits[ ( @digits.elems / 2 ).Int ] != any ( 0, 1 , 8 );
+
+            my $ok = True;
+            CHECKING:
+            for 0 ..^ @digits.elems -> $index {
+                my ( $left, $right ) = $index, @digits.elems - $index - 1;
+                last if $left == $right || $left > $right;
+                $ok = False if ( %reverse{ @digits[ $left ] }:!exists )
+                || ( %reverse{ @digits[ $right ] }:!exists );
+
+                last CHECKING if ! $ok;
+                $ok &= %reverse{ @digits[ $left ] } == @digits[ $right ];
+                last CHECKING if ! $ok;
+            }
+
+            take $_ if $ok;
+        }
+    } # end of gather
+
+
+    @found.unique.join( ', ' ).say;
+
+}
diff --git a/challenge-069/luca-ferrari/raku/ch-2.p6 b/challenge-069/luca-ferrari/raku/ch-2.p6
new file mode 100644
index 0000000000..4603520f6f
--- /dev/null
+++ b/challenge-069/luca-ferrari/raku/ch-2.p6
@@ -0,0 +1,31 @@
+#!raku
+
+
+
+sub switch( Str $string where { $string ~~ / ^ <[0 1]>+ $ / } ) {
+    my @bits;
+    for $string.split( '', :skip-empty ) {
+        @bits.push( 0 ) && next if $_ == 1;
+        @bits.push: 1 if $_ == 0;
+    }
+
+    @bits.join;
+}
+
+
+sub reverse( Str $string where { $string ~~ / ^ <[0 1]>+ $ / } ) {
+    $string.split( '', :skip-empty ).reverse.join;
+}
+
+sub MAIN( Int:D $max? = 100  ) {
+    my $current-string;
+    for 0 .. $max {
+        $current-string = ''  if $_ == 0;
+        $current-string = '0' if $_ == 1;
+        next if $_ <= 1;
+        $current-string = $current-string ~ '0' ~ switch( reverse( $current-string ) );
+    }
+
+    $current-string.csay;
+
+}