Create staircase.py

algo/cracking_coding_interview/staircase.py

@@ -0,0 +1,17 @@
+#!/bin/python3
+
+import math
+import os
+import random
+import re
+import sys
+from functools import lru_cache
+
+# Complete the stepPerms function below.
+@lru_cache(maxsize=128)
+def stepPerms(n):
+    if n < 0:
+        return 0
+    if n == 0 or n == 1:
+        return 1
+    return stepPerms(n-1) + stepPerms(n-2) + stepPerms(n-3)