diff --git a/contains-duplicate/seona926.js b/contains-duplicate/seona926.js
new file mode 100644
index 000000000..2721c3e59
--- /dev/null
+++ b/contains-duplicate/seona926.js
@@ -0,0 +1,16 @@
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+let containsDuplicate = function (nums) {
+  let counts = {};
+
+  return nums.some((num) => {
+    if (counts[num] === undefined) {
+      counts[num] = 1;
+      return false;
+    } else {
+      return true;
+    }
+  });
+};
diff --git a/number-of-1-bits/seona926.js b/number-of-1-bits/seona926.js
new file mode 100644
index 000000000..a3def9ccf
--- /dev/null
+++ b/number-of-1-bits/seona926.js
@@ -0,0 +1,19 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+let hammingWeight = function (n) {
+  let count = 0;
+  let sum = n;
+
+  while (sum > 0) {
+    // n에서 가장 오른쪽 비트가 1인 경우 count 증가
+    if (sum % 2 === 1) {
+      count++;
+    }
+    // sum을 2로 나누어서 다음 비트를 확인
+    sum = Math.floor(sum / 2);
+  }
+
+  return count;
+};