Week 02: climbing-stairs solution

Author: mandel-17

climbing-stairs/mandel-17.py

@@ -0,0 +1,23 @@
+class Solution:
+    def climbStairs(self, n: int) -> int:
+        def factorial(n):
+            result = 1
+            for i in range(1, n+1):
+                result *= i
+            return result
+
+        def combination(n, r):
+            top = factorial(n)
+            bottom = factorial(n-r) * factorial(r)
+            return top / bottom
+
+        share = n // 2
+        total = 1
+        for i in range(1, share + 1):
+            combination_n = n - i
+            combination_r = i
+
+            total += combination(combination_n, combination_r)
+
+        return int(total)
+