From 9403c2168a7977c82988951518e38ab5c8b53fef Mon Sep 17 00:00:00 2001
From: Dale Seo <5466341+DaleSeo@users.noreply.github.com>
Date: Wed, 11 Mar 2026 19:40:32 -0400
Subject: [PATCH] climbing-stairs

---
 climbing-stairs/DaleSeo.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 climbing-stairs/DaleSeo.rs

diff --git a/climbing-stairs/DaleSeo.rs b/climbing-stairs/DaleSeo.rs
new file mode 100644
index 000000000..dd65a89ea
--- /dev/null
+++ b/climbing-stairs/DaleSeo.rs
@@ -0,0 +1,16 @@
+// TC: O(n)
+// SC: O(1)
+impl Solution {
+    pub fn climb_stairs(n: i32) -> i32 {
+        if n < 3 {
+            return n;
+        }
+        let (mut pre, mut cur) = (1, 2);
+        for _ in 3..=n {
+            let next = pre + cur;
+            pre = cur;
+            cur = next;
+        }
+        cur
+    }
+}