From 36250b3538395e236104f69b6af2c74bc094ea90 Mon Sep 17 00:00:00 2001
From: seungseung88 <lisu5336@gmail.com>
Date: Tue, 15 Apr 2025 20:54:02 +0900
Subject: [PATCH 1/3] =?UTF-8?q?=ED=92=80=EC=9D=B41:=20Valid=20Palindrome?=
 =?UTF-8?q?=20#220?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 valid-palindrome/seungseung88.js | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 valid-palindrome/seungseung88.js

diff --git a/valid-palindrome/seungseung88.js b/valid-palindrome/seungseung88.js
new file mode 100644
index 000000000..5de488fc4
--- /dev/null
+++ b/valid-palindrome/seungseung88.js
@@ -0,0 +1,25 @@
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+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;
+};

From 56f96eb6b9661d727d8b089cda1d95213dae53d7 Mon Sep 17 00:00:00 2001
From: seungseung88 <lisu5336@gmail.com>
Date: Wed, 16 Apr 2025 22:31:07 +0900
Subject: [PATCH 2/3] Number of 1 Bits #232

---
 number-of-1-bits/seungseung88.js | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 number-of-1-bits/seungseung88.js

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;
+};

From 3fc20a056e246108276b7a7615521a18ba266c4e Mon Sep 17 00:00:00 2001
From: seungseung88 <lisu5336@gmail.com>
Date: Wed, 16 Apr 2025 23:11:00 +0900
Subject: [PATCH 3/3] =?UTF-8?q?=ED=92=80=EC=9D=B42:=20=EA=B3=B5=EA=B0=84?=
 =?UTF-8?q?=20=EB=B3=B5=EC=9E=A1=EB=8F=84O(n)=20->=20O(1)=20=20Valid=20Pal?=
 =?UTF-8?q?indrome=20#220?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 valid-palindrome/seungseung88.js | 56 ++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 10 deletions(-)

diff --git a/valid-palindrome/seungseung88.js b/valid-palindrome/seungseung88.js
index 5de488fc4..20a759eea 100644
--- a/valid-palindrome/seungseung88.js
+++ b/valid-palindrome/seungseung88.js
@@ -1,25 +1,61 @@
 /**
- * @param {string} s
- * @return {boolean}
+ * 시간 복잡도: O(n)
+ * 공간 복잡도: O(n)
  */
-var isPalindrome = function (s) {
-  // 숫자와 문자만 추출하는 정규식
-  const REGEX = /[0-9a-zA-Z]/g;
+// 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;
+//   }
 
-  const wordArr = s.match(REGEX);
+//   return true;
+// };
 
-  // 문자가 비어있으면 true반환
-  if (!wordArr) 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 = wordArr.length - 1;
+  let r = s.length - 1;
 
   while (l < r) {
-    if (wordArr[l].toLocaleLowerCase() !== wordArr[r].toLocaleLowerCase()) return false;
     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));