Climbing Stairs

Author: hyejjun

climbing-stairs/hyejjun.js

@@ -0,0 +1,28 @@
+/**
+ * @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 third = first + second;
+    first = second;
+    second = third;
+  }
+
+  return second;
+};
+
+console.log(climbStairs(2));
+console.log(climbStairs(3));
+console.log(climbStairs(4));
+console.log(climbStairs(5));
+
+/*
+시간 복잡도: O(n)
+공간 복잡도: O(1)
+*/