diff --git a/number-of-1-bits/seungseung88.js b/number-of-1-bits/seungseung88.js
new file mode 100644
index 000000000..fe52a4243
--- /dev/null
+++ b/number-of-1-bits/seungseung88.js
@@ -0,0 +1,28 @@
+/**
+ * 시간 복잡도: O(log n)
+ * 공간 복잡도: O(n)
+ */
+//
+var hammingWeight = function (n) {
+  let count = 0;
+
+  while (n > 0) {
+    if (n % 2) count += 1;
+
+    // Math.floor랑 같은 역할
+    n = ~~(n / 2);
+  }
+
+  return count;
+};
+
+// 비트 연산자 사용
+var hammingWeight = function (n) {
+  let count = 0;
+  while (num > 0) {
+    if (n & 1) count += 1;
+    n >>>= 1;
+  }
+
+  return countOne;
+};
diff --git a/valid-palindrome/seungseung88.js b/valid-palindrome/seungseung88.js
new file mode 100644
index 000000000..20a759eea
--- /dev/null
+++ b/valid-palindrome/seungseung88.js
@@ -0,0 +1,61 @@
+/**
+ * 시간 복잡도: O(n)
+ * 공간 복잡도: O(n)
+ */
+// var isPalindrome = function (s) {
+//   // 숫자와 문자만 추출하는 정규식
+//   const REGEX = /[0-9a-zA-Z]/g;
+
+//   const wordArr = s.match(REGEX);
+
+//   // 문자가 비어있으면 true반환
+//   if (!wordArr) return true;
+
+//   let l = 0;
+//   let r = wordArr.length - 1;
+
+//   while (l < r) {
+//     if (wordArr[l].toLocaleLowerCase() !== wordArr[r].toLocaleLowerCase()) return false;
+//     console.log(l, r);
+//     l += 1;
+//     r -= 1;
+//   }
+
+//   return true;
+// };
+
+/**
+ * 시간 복잡도: O(n)
+ * 공간 복잡도: 1
+ */
+var isPalindrome = function (s) {
+  // 숫자와 문자만 추출하는 정규식
+  const isAlnum = (char) =>
+    (char >= 'a' && char <= 'z') || (char >= 'A' && char <= 'Z') || (char >= '0' && char <= '9');
+
+  let l = 0;
+  let r = s.length - 1;
+
+  while (l < r) {
+    console.log(l, r);
+    if (!isalnum.test(s[l])) {
+      l += 1;
+      continue;
+    }
+    if (!isalnum.test(s[r])) {
+      r -= 1;
+      continue;
+    }
+    if (s[l].toLowerCase() !== s[r].toLowerCase()) {
+      return false;
+    }
+    l += 1;
+    r -= 1;
+  }
+
+  return true;
+};
+
+const s = 'A man, a plan, a canal: Panama';
+
+console.log(isPalindrome(s));