climbing stairs solution

Author: bhan

climbing-stairs/byol-han.js

@@ -0,0 +1,17 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var climbStairs = function (n) {
+  if (n <= 2) return n;
+
+  let first = 1;
+  let second = 2;
+
+  for (let i = 3; i <= n; i++) {
+    let count = first + second;
+    first = second;
+    second = count;
+  }
+  return second;
+};