feat: optimize climbing-stairs

Author: lylaminju

climbing-stairs/pmjuu.py

@@ -15,3 +15,16 @@ def climbStairs(self, n: int) -> int:
 # Complexity
 # - time: O(n)
 # - space: O(n)
+
+class Solution:
+    def climbStairs(self, n: int) -> int:
+        prev, curr = 1, 1
+
+        for _ in range(2, n + 1):
+            prev, curr = curr, prev + curr
+        
+        return curr
+    
+# Complexity
+# - time: O(n)
+# - space: O(1)