a solution to pwc 096.2 in Raku. (Levinstein edit distance)

1 files changed, 26 insertions, 0 deletions

diff --git a/challenge-096/gugod/raku/ch-2.raku b/challenge-096/gugod/raku/ch-2.raku
new file mode 100644
index 0000000000..bf2e2a1357
--- /dev/null
+++ b/challenge-096/gugod/raku/ch-2.raku
@@ -0,0 +1,26 @@
+sub MAIN {
+    my @examples = (
+        [ 'kitten', 'sitting' ],
+        [ 'sunday', 'monday' ],
+    );
+
+    for @examples -> ($S1, $S2) {
+        say "Input: \$S1 = $S1, \$S2 = $S2";
+        say "Output: " ~ edit-distance($S1, $S2);
+    }
+}
+
+sub edit-distance (Str $S1, Str $S2 --> Int) {
+    my sub lev ($a, $b) {
+        return $a.chars if $b.chars == 0;
+        return $b.chars if $a.chars == 0;
+        return lev( $a.substr(1), $b.substr(1) ) if $a.substr(0,1) eq $b.substr(0,1);
+        return 1 + (
+            lev($a, $b.substr(1)),
+            lev($a.substr(1), $b),
+            lev($a.substr(1), $b.substr(1)),
+        ).min;
+    };
+
+    return lev($S1, $S2);
+}