Data update

Task/Entropy/PascalABC.NET/entropy.pas

@@ -0,0 +1,13 @@
+function entropy(s: string): real;
+begin
+  result := 0.0;
+  foreach var c in s.distinct do
+  begin
+    var freq := s.count(x -> x = c) / s.length;
+    result += -freq * log2(freq);
+  end;
+end;
+
+begin
+  entropy('1223334444').println;
+end