From 26ef844e9f4927ba1a80ecfa4b01c022f3945642 Mon Sep 17 00:00:00 2001
From: herrinekim <herrine.kim@gmail.com>
Date: Sat, 21 Dec 2024 02:14:55 +0900
Subject: [PATCH 1/2] add: solutions for 3 problems

---
 climbing-stairs/HerrineKim.js | 17 +++++++++++++++++
 decode-ways/HerrineKim.js     | 26 ++++++++++++++++++++++++++
 valid-anagram/HerrineKim.js   | 27 +++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 climbing-stairs/HerrineKim.js
 create mode 100644 decode-ways/HerrineKim.js
 create mode 100644 valid-anagram/HerrineKim.js

diff --git a/climbing-stairs/HerrineKim.js b/climbing-stairs/HerrineKim.js
new file mode 100644
index 000000000..53db3b626
--- /dev/null
+++ b/climbing-stairs/HerrineKim.js
@@ -0,0 +1,17 @@
+// 시간복잡도: O(n)
+// 공간복잡도: O(1)
+
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var climbStairs = function (n) {
+  if (n <= 2) return n;
+  let prev1 = 1, prev2 = 2;
+  for (let i = 3; i <= n; i++) {
+    let curr = prev1 + prev2;
+    prev1 = prev2;
+    prev2 = curr;
+  }
+  return prev2;
+};
diff --git a/decode-ways/HerrineKim.js b/decode-ways/HerrineKim.js
new file mode 100644
index 000000000..0c0068885
--- /dev/null
+++ b/decode-ways/HerrineKim.js
@@ -0,0 +1,26 @@
+// 시간복잡도: O(n)
+// 공간복잡도: O(n)
+
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var numDecodings = function (s) {
+  const memo = {};
+
+  const helper = (index) => {
+    if (index === s.length) return 1;
+    if (s[index] === '0') return 0;
+    if (memo[index] !== undefined) return memo[index];
+
+    let ways = helper(index + 1);
+    if (index < s.length - 1 && parseInt(s.slice(index, index + 2)) <= 26) {
+      ways += helper(index + 2);
+    }
+
+    memo[index] = ways;
+    return ways;
+  };
+
+  return helper(0);
+};
diff --git a/valid-anagram/HerrineKim.js b/valid-anagram/HerrineKim.js
new file mode 100644
index 000000000..a10713246
--- /dev/null
+++ b/valid-anagram/HerrineKim.js
@@ -0,0 +1,27 @@
+// 시간복잡도: O(n)
+// 공간복잡도: O(1)
+
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+var isAnagram = function (s, t) {
+  if (s.length !== t.length) return false;
+
+  const charCount = {};
+
+  for (const char of s) {
+    charCount[char] = (charCount[char] || 0) + 1;
+  }
+
+  for (const char of t) {
+    if (!charCount[char]) {
+      return false;
+    }
+    charCount[char]--;
+  }
+
+  return true;
+};
+

From 67ae62170697a69389d80ac9fdf2882748115359 Mon Sep 17 00:00:00 2001
From: herrinekim <herrine.kim@gmail.com>
Date: Sat, 21 Dec 2024 02:17:15 +0900
Subject: [PATCH 2/2] fix: add empty lines

---
 climbing-stairs/HerrineKim.js | 1 +
 decode-ways/HerrineKim.js     | 1 +
 2 files changed, 2 insertions(+)

diff --git a/climbing-stairs/HerrineKim.js b/climbing-stairs/HerrineKim.js
index 53db3b626..37dcbf3e1 100644
--- a/climbing-stairs/HerrineKim.js
+++ b/climbing-stairs/HerrineKim.js
@@ -15,3 +15,4 @@ var climbStairs = function (n) {
   }
   return prev2;
 };
+
diff --git a/decode-ways/HerrineKim.js b/decode-ways/HerrineKim.js
index 0c0068885..ea2335cd2 100644
--- a/decode-ways/HerrineKim.js
+++ b/decode-ways/HerrineKim.js
@@ -24,3 +24,4 @@ var numDecodings = function (s) {
 
   return helper(0);
 };
+