Data commit

Task/Ackermann-function/Python/ackermann-function-5.py

@@ -0,0 +1,25 @@
+from collections import deque
+
+def ack_ix(m, n):
+    "Paddy3118's iterative with optimisations on m"
+
+    stack = deque([])
+    stack.extend([m, n])
+
+    while  len(stack) > 1:
+        n, m = stack.pop(), stack.pop()
+
+        if   m == 0:
+            stack.append(n + 1)
+        elif m == 1:
+            stack.append(n + 2)
+        elif m == 2:
+            stack.append(2*n + 3)
+        elif m == 3:
+            stack.append(2**(n + 3) - 3)
+        elif n == 0:
+            stack.extend([m-1, 1])
+        else:
+            stack.extend([m-1, m, n-1])
+
+    return stack[0]