climbing stairs solution

Author: jylee2033

climbing-stairs/jylee2033.py

@@ -0,0 +1,20 @@
+class Solution:
+    def climbStairs(self, n: int) -> int:
+        # ways(n) = ways(n-1) + ways(n-2)
+
+        if n == 1:
+            return 1
+        elif n == 2:
+            return 2
+
+        ways = [0] * (n + 1)
+        ways[1] = 1
+        ways[2] = 2
+
+        for i in range(3, n + 1):
+            ways[i] = ways[i - 1] + ways[i - 2]
+
+        return ways[n]
+
+# Time Complexity: O(n)
+# Space Complexity: O(n)