big numbers fix

Author: DiedCloud

task20/lib/iterative.ml

@@ -1,18 +1,28 @@
+let scale digits factor =
+  let acc = ref [] in
+  let carry = ref 0 in
+  List.iter (fun hd ->
+    let prod = hd * factor + !carry in
+    acc := (prod mod 10) :: !acc;
+    carry := prod / 10
+  ) digits;
+  while !carry > 0 do
+    acc := (!carry mod 10) :: !acc;
+    carry := !carry / 10
+  done;
+  List.rev !acc
+
 let factorial n =
-  let res = ref 1 in
+  let result = ref [1] in
   for i = 2 to n do
-    res := !res * i
+    result := scale !result i
   done;
-  !res;;
+  !result
 
-let sum_of_digits n =
-  let res = ref 1 in
-  let temp_n = ref n in
-  while !temp_n > 0 do
-    res := !res * (!temp_n mod 10);
-    temp_n := !temp_n / 10
-  done;
-  !res;;
+let sum_of_digits digits =
+  let sum = ref 0 in
+  List.iter (fun d -> sum := !sum + d) digits;
+  !sum
 
 let solve n = sum_of_digits (factorial n)
 

task20/lib/recursion.ml

@@ -1,9 +1,20 @@
-let rec factorial n = if n = 0 then 1 else n * factorial (n - 1)
+let rec scale digits factor carry =
+  match digits with
+  | [] -> if carry > 0 then (carry mod 10) :: scale [] factor (carry / 10) else []
+  | hd :: tl ->
+      let prod = hd * factor + carry in
+      (prod mod 10) :: scale tl factor (prod / 10)
 
-let rec sum_of_digits n =
-  if n = 0 then 0 else (n mod 10) + sum_of_digits (n / 10)
+let rec multiply acc i n =
+  if i > n then acc
+  else multiply (scale acc i 0) (i + 1) n
 
-let solve n = sum_of_digits (factorial n)
+let rec sum_of_digits = function
+  | [] -> 0
+  | hd :: tl -> hd + sum_of_digits tl
+
+let solve n =
+  sum_of_digits (multiply [1] 2 n)
 
 (* Пример использования *)
 let result = solve 100;;

task20/lib/tail_recursion.ml

@@ -1,18 +1,24 @@
-let factorial n =
-  let rec aux acc n =
-    if n = 0 then acc else aux (acc * n) (n - 1)
-  in
-  aux 1 n
+let rec scale digits factor carry acc =
+  match digits with
+  | [] -> if carry > 0 then scale digits factor (carry / 10) ((carry mod 10) :: acc) else acc
+  | hd :: tl ->
+      let prod = hd * factor + carry in
+      scale tl factor (prod / 10) ((prod mod 10) :: acc)
 
-let sum_of_digits n =
-  let rec aux acc n =
-    if n = 0 then acc else aux (acc + (n mod 10)) (n / 10)
-  in
-  aux 0 n
+let scale_tail digits factor =
+  List.rev (scale digits factor 0 [])
+
+let rec multiply acc i n =
+  if i > n then acc
+  else multiply (scale_tail acc i) (i + 1) n
+
+let rec sum_of_digits digits acc =
+  match digits with
+  | [] -> acc
+  | hd :: tl -> sum_of_digits tl (hd + acc)
 
 let solve n =
-  let fact = factorial n in
-  sum_of_digits fact
+  sum_of_digits (multiply [1] 2 n) 0
 
 (* Пример использования *)
 let result = solve 100;;

task20/test/test_task20.ml

@@ -3,32 +3,34 @@ open Task20_lib
 
 (* Tailrec tests *)
 let test_tailrec _ =
-  assert_equal 3 (Tail_recursion.solve 5)
+  assert_equal 3 (Tail_recursion.solve 5);;
+  assert_equal 648 (Tail_recursion.solve 100);;
 ;;
 
 (* Rec tests *)
 let test_rec _ =
-  assert_equal 3 (Recursion.solve 5)
+  assert_equal 3 (Recursion.solve 5);;
+  assert_equal 648 (Recursion.solve 100);;
 ;;
 
 (* Module tests *)
 let test_moduled _ =
-  assert_equal 3 (Moduled.solve 5)
-;;
+  assert_equal 3 (Moduled.solve 5);;
 
 (* Iterative tests*)
 let test_iterative _ =
-  assert_equal 3 (Iterative.solve 5)
+  assert_equal 3 (Iterative.solve 5);;
+  assert_equal 648 (Iterative.solve 100);;
 ;;
 
 (* Map tests *)
 let test_mapped _ =
-  assert_equal 3 (Mapped.solve 5)
+  assert_equal 3 (Mapped.solve 5);;
 ;;
 
 (* Lazy collections tests *)
 let test_lazy _ =
-  assert_equal 3 (Lazy.solve 5)
+  assert_equal 3 (Lazy.solve 5);;
 ;;
 
 let suite =