Initial data commit

Task/Burrows-Wheeler-transform/Sidef/burrows-wheeler-transform.sidef

@@ -0,0 +1,29 @@
+class BurrowsWheelerTransform (String L = "\002") {
+
+    method encode(String s) {
+        assert(!s.contains(L), "String cannot contain `#{L.dump}`")
+        s = (L + s)
+        s.len.of{|i| s.substr(i) + s.substr(0, i) }.sort.map{.last}.join
+    }
+
+    method decode(String s) {
+        var t = s.len.of("")
+        var c = s.chars
+        { t = (c »+« t).sort } * s.len
+        t.first { .begins_with(L) }.substr(L.len)
+    }
+}
+
+var tests = [
+    "banana", "appellee", "dogwood", "TOBEORNOTTOBEORTOBEORNOT"
+    "SIX.MIXED.PIXIES.SIFT.SIXTY.PIXIE.DUST.BOXES",
+]
+
+var bwt = BurrowsWheelerTransform(L: '$')
+
+tests.each { |str|
+    var enc = bwt.encode(str)
+    var dec = bwt.decode(enc)
+    say "BWT(#{dec.dump}) = #{enc.dump}"
+    assert_eq(str, dec)
+}