solve: climbing stairs

Author: 김가은

climbing-stairs/paran22.py

@@ -0,0 +1,12 @@
+class Solution:
+    # time complexity: O(n)
+    def climbStairs(self, n: int) -> int:
+        if n <= 2:
+            return n
+    
+        prev1, prev2 = 1, 2
+        for _ in range(3, n + 1):
+            current = prev1 + prev2
+            prev1, prev2 = prev2, current
+        return prev2
+