From 8d30b5f8592e03219d818ca45a08c9ce0829a520 Mon Sep 17 00:00:00 2001
From: Cyjin-jani <jinjanic91@gmail.com>
Date: Tue, 17 Mar 2026 15:52:14 +0900
Subject: [PATCH 1/2] add: validPalindrome solution

---
 valid-palindrome/Cyjin-jani.js | 41 ++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 valid-palindrome/Cyjin-jani.js

diff --git a/valid-palindrome/Cyjin-jani.js b/valid-palindrome/Cyjin-jani.js
new file mode 100644
index 000000000..c5052d316
--- /dev/null
+++ b/valid-palindrome/Cyjin-jani.js
@@ -0,0 +1,41 @@
+// naive한 풀이
+// tc: O(n)
+// sc: O(n)
+const isPalindromeNaive = function (s) {
+  const str = s.toLowerCase().replace(/[^a-z0-9]/g, ''); // 이 부분에서 공간복잡도가 O(n)
+  let leftIdx = 0;
+  let rightIdx = str.length - 1;
+
+  while (leftIdx <= rightIdx) {
+    if (str[leftIdx] !== str[rightIdx]) {
+      return false;
+    } else {
+      leftIdx++;
+      rightIdx--;
+    }
+  }
+  return true;
+};
+
+// 좀 더 최적화 된 풀이
+// tc: O(n)
+// cs: O(1)
+const isPalindrome = function (s) {
+  let leftIdx = 0;
+  let rightIdx = s.length - 1;
+
+  while (leftIdx < rightIdx) {
+    while (leftIdx < rightIdx && !isAlphaNumeric(s[leftIdx])) leftIdx++;
+    while (leftIdx < rightIdx && !isAlphaNumeric(s[rightIdx])) rightIdx--;
+
+    if (s[leftIdx].toLowerCase() !== s[rightIdx].toLowerCase()) return false;
+
+    leftIdx++;
+    rightIdx--;
+  }
+  return true;
+};
+
+function isAlphaNumeric(char) {
+  return /[a-zA-Z0-9]/.test(char);
+}

From f886f0b1018ae409a0536abc00bce67fbaf49105 Mon Sep 17 00:00:00 2001
From: Cyjin-jani <jinjanic91@gmail.com>
Date: Tue, 17 Mar 2026 16:14:24 +0900
Subject: [PATCH 2/2] add: numberOf1Bits solution

---
 number-of-1-bits/Cyjin-jani.js | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 number-of-1-bits/Cyjin-jani.js

diff --git a/number-of-1-bits/Cyjin-jani.js b/number-of-1-bits/Cyjin-jani.js
new file mode 100644
index 000000000..e8011574b
--- /dev/null
+++ b/number-of-1-bits/Cyjin-jani.js
@@ -0,0 +1,29 @@
+// tc: O(logn)
+// sc: O(logn)
+const hammingWeight_simple = function (n) {
+  const binaryStr = n.toString(2);
+  let answer = 0;
+
+  for (char of binaryStr) {
+    if (+char === 1) {
+      answer++;
+    }
+  }
+
+  return answer;
+};
+
+// toString(2)를 쓰지 않고 처리
+// tc: O(logn)
+// sc: O(1)
+const hammingWeight = function (n) {
+  let answer = 0;
+
+  while (n >= 0) {
+    const remains = n % 2;
+    if (remains === 1) answer++;
+    n = Math.floor(n / 2);
+  }
+
+  return answer;
+};