View difference between Paste ID: ZYqTP53y and TD3w1eRq

 open Printf
 
 type exp =
 | Impossible
 | Eight
 | Add of exp * exp
 | Sub of exp * exp
 | Div of exp * exp
 | Mul of exp * exp
 | Sqrt of exp
 
 let rec print out = function
 | Impossible -> ()
 | Eight -> fprintf out "8"
 | Add (a,b) -> fprintf out "(%a + %a)" print a print b
 | Sub (a,b) -> fprintf out "(%a - %a)" print a print b
 | Div (a,b) -> fprintf out "(%a / %a)" print a print b
 | Mul (a,b) -> fprintf out "(%a * %a)" print a print b
 | Sqrt (a) -> fprintf out "sqrt(%a)" print a
 
 let n = 256
 let c = 4
 
 let mem = Array.init c (fun _ -> Array.make n Impossible)
 let expressions = ref []
 
 let rec enum exp count value =
   if value > 0 && value <= n &&
      count > 0 && count <= c &&
      mem.(count-1).(value-1) = Impossible then
   begin
     mem.(count-1).(value-1) <- exp ;
     expressions := (exp,count,value) :: !expressions ;
 
-      for i = 0 to c-1 do
+
-        for j = 0 to n-1 do
+
-          let exp' = mem.(i).(j)
+      let f (exp',count',value') =
-          and count' = i+1
+        enum (Add (exp, exp')) (count + count') (value + value') ;
-          and value' = j+1 in
+        enum (Sub (exp, exp')) (count + count') (value - value') ;
-          if exp' <> Impossible then
+        enum (Sub (exp', exp)) (count + count') (value' - value) ;
-          begin
+        enum (Mul (exp, exp')) (count + count') (value * value') ;
-            enum (Add (exp, exp')) (count + count') (value + value') ;
+        if value mod value' = 0 then
-            enum (Sub (exp, exp')) (count + count') (value - value') ;
+          enum (Div (exp, exp')) (count + count') (value / value') ;
-            enum (Sub (exp', exp)) (count + count') (value' - value) ;
+        if value' mod value = 0 then
-            enum (Mul (exp, exp')) (count + count') (value * value') ;
+          enum (Div (exp', exp)) (count + count') (value' / value) ;
-            if value mod value' = 0 then
+      in
-              enum (Div (exp, exp')) (count + count') (value / value') ;
+      List.iter f !expressions
-            if value' mod value = 0 then
+
-              enum (Div (exp', exp)) (count + count') (value' / value) ;
+
-          end
+
-        done
+
-      done
+
       enum (Sqrt exp) count iroot ;
   end
 
 let _ =
   enum Eight 1 8 ;
   for j = 0 to 29 do
     printf "%d: %a\n" (j+1) print mem.(c-1).(j) ;
   done