From c6f76088f39b8572e1520db9a4e1c2fa8eb318fe Mon Sep 17 00:00:00 2001
From: Jeongmin Lee <clcl6084@gmail.com>
Date: Wed, 16 Apr 2025 13:29:22 +0900
Subject: [PATCH 1/3] valid palindrome solution

---
 valid-palindrome/froggy1014.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 valid-palindrome/froggy1014.js

diff --git a/valid-palindrome/froggy1014.js b/valid-palindrome/froggy1014.js
new file mode 100644
index 000000000..dc3ee4947
--- /dev/null
+++ b/valid-palindrome/froggy1014.js
@@ -0,0 +1,22 @@
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+
+var isPalindrome = function (s) {
+  const str = s.replace(/[^a-zA-Z0-9]/g, "").toLowerCase();
+  let left = 0;
+  let right = str.length - 1;
+
+  while (left < right) {
+    if (str[left] !== str[right]) return false;
+    left++;
+    right--;
+  }
+
+  return true;
+};
+
+console.log(isPalindrome("A man, a plan, a canal: Panama"));
+console.log(isPalindrome("race a car"));
+console.log(isPalindrome(" "));

From 8e138a4535366d022371caadc8866cfd9995c363 Mon Sep 17 00:00:00 2001
From: Jeongmin Lee <clcl6084@gmail.com>
Date: Wed, 16 Apr 2025 13:35:45 +0900
Subject: [PATCH 2/3] add complexity

---
 valid-palindrome/froggy1014.js | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/valid-palindrome/froggy1014.js b/valid-palindrome/froggy1014.js
index dc3ee4947..8e0283678 100644
--- a/valid-palindrome/froggy1014.js
+++ b/valid-palindrome/froggy1014.js
@@ -1,8 +1,5 @@
-/**
- * @param {string} s
- * @return {boolean}
- */
-
+// Time Complexity O(n)
+// Space Complexity O(n)
 var isPalindrome = function (s) {
   const str = s.replace(/[^a-zA-Z0-9]/g, "").toLowerCase();
   let left = 0;

From 521e92318e5cf08951e650f41692492c9fefd250 Mon Sep 17 00:00:00 2001
From: Jeongmin Lee <clcl6084@gmail.com>
Date: Thu, 17 Apr 2025 13:53:10 +0900
Subject: [PATCH 3/3] add number of 1 bits solution

---
 number-of-1-bits/froggy1014.js | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 number-of-1-bits/froggy1014.js

diff --git a/number-of-1-bits/froggy1014.js b/number-of-1-bits/froggy1014.js
new file mode 100644
index 000000000..08b1bad5c
--- /dev/null
+++ b/number-of-1-bits/froggy1014.js
@@ -0,0 +1,31 @@
+
+// Time complexity: O(k)
+// Space complexity: O(k)
+
+/**
+ * @param {number} n
+ * @return {number}
+ */
+
+// 문자열 변환을 사용한 풀이 
+// 이진수로 변환된 수를 문자열로 변환후 1의 개수를 세는 방법
+// 문자열 변환은 비트 연산자보다 느리지만 이해하기 쉬운 방법
+var hammingWeight = function (n) {
+  return n.toString(2).split('').filter(b => b === '1').length
+}
+
+// Time complexity: O(1)
+// Space complexity: O(1)
+
+// 비트 연산자를 사용한 풀이
+// 비트 연산자는 이진수로 변환된 수를 비교하는 연산자
+// 자바스크립트 엔진이 숫자를 32비트 정수로 변환후 CPU 수준에서 연산을 수행
+var hammingWeight = function (n) {
+  let count = 0;
+  for (let i = 0; i < 32; i++) {
+    if ((n & (1 << i)) !== 0) {
+      count++;
+    }
+  }
+  return count;
+};