diff --git a/climbing-stairs/hyejjun.js b/climbing-stairs/hyejjun.js
new file mode 100644
index 000000000..f2f6f306f
--- /dev/null
+++ b/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)
+*/
diff --git a/two-sum/hyejjun.js b/two-sum/hyejjun.js
new file mode 100644
index 000000000..6abf6a87f
--- /dev/null
+++ b/two-sum/hyejjun.js
@@ -0,0 +1,23 @@
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+var twoSum = function (nums, target) {
+  for (let i = 0; i < nums.length; i++) {
+    for (let j = i + 1; j < nums.length; j++) {
+      if (nums[i] + nums[j] === target) {
+        return [i, j];
+      }
+    }
+  }
+};
+
+console.log(twoSum([2, 7, 11, 15], 9));
+console.log(twoSum([3, 2, 4], 6));
+console.log(twoSum([3, 3], 6));
+
+/*
+시간 복잡도: O(n^2)
+공간 복잡도: O(1)
+*/