Merge pull request #2415 from DaleStudy/week2

[DaleSeo] WEEK 2 Solutions

Author: DaleSeo

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
+    }
+}