finish: easy 0070

Author: benben6515

leetcode-easy/0070-climbing-stairs.js

@@ -0,0 +1,18 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var climbStairs = function(n) {
+  let prev = 1
+  let step = 1
+  for (let i = 2; i < n + 1; i++) {
+    let temp = step
+    step = prev + step
+    prev = temp
+  }
+  return step
+};
+
+// 2022/07/06 done.
+// Runtime: 58 ms, faster than 96.04% of JavaScript online submissions for Climbing Stairs.
+// Memory Usage: 42.1 MB, less than 30.47% of JavaScript online submissions for Climbing Stairs.