September 2017 Update

Task/Rep-string/Jq/rep-string-1.jq

@@ -0,0 +1,20 @@
+def is_rep_string:
+  # if self is a rep-string then return [n, prefix]
+  # where n is the number of full occurrences of prefix
+  def _check(prefix; n; sofar):
+    length as $length
+    | if length <= (sofar|length) then [n, prefix]
+      else (sofar+prefix) as $sofar
+      | if  startswith($sofar) then _check(prefix; n+1; $sofar)
+        elif ($sofar|length) > $length and
+             startswith($sofar[0:$length]) then [n, prefix]
+        else [0, prefix]
+        end
+      end
+  ;
+
+  [range (1; length/2 + 1) as $i
+     | .[0:$i] as $prefix
+     | _check($prefix; 1; $prefix)
+     | select( .[0] > 1 ) ]
+  ;