From 02a47a27b756796b060a0c181b40ad4434d40775 Mon Sep 17 00:00:00 2001
From: Sangmin <sm9171@nate.com>
Date: Tue, 8 Apr 2025 20:26:05 +0900
Subject: [PATCH 1/4] feat: valid-anagram solution

---
 valid-anagram/sm9171.java | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 valid-anagram/sm9171.java

diff --git a/valid-anagram/sm9171.java b/valid-anagram/sm9171.java
new file mode 100644
index 000000000..aa6400a96
--- /dev/null
+++ b/valid-anagram/sm9171.java
@@ -0,0 +1,24 @@
+class Solution {
+    public boolean isAnagram(String s, String t) {
+        if (s.length() != t.length()) {
+            return false;
+        }
+
+        HashMap<Character, Integer> map = new HashMap<>();
+        char[] originString = s.toCharArray();
+        for (int i = 0; i < originString.length; i++) {
+            Integer count = map.getOrDefault(originString[i], 0);
+            map.put(originString[i], count + 1);
+        }
+
+        char[] targetString = t.toCharArray();
+        for (int i = 0; i < targetString.length; i++) {
+            Integer count = map.get(targetString[i]);
+            if (count == null || count == 0) {
+                return false;
+            }
+            map.put(targetString[i], count - 1);
+        }
+        return true;
+    }
+}
\ No newline at end of file

From 827238989e0404072aeb233d794714da6bb42442 Mon Sep 17 00:00:00 2001
From: Sangmin <sm9171@nate.com>
Date: Tue, 8 Apr 2025 20:31:55 +0900
Subject: [PATCH 2/4] style: add eol

---
 valid-anagram/sm9171.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/valid-anagram/sm9171.java b/valid-anagram/sm9171.java
index aa6400a96..b44cf14a1 100644
--- a/valid-anagram/sm9171.java
+++ b/valid-anagram/sm9171.java
@@ -21,4 +21,4 @@ public boolean isAnagram(String s, String t) {
         }
         return true;
     }
-}
\ No newline at end of file
+}

From 536fe6a6cde60a74bf13dd19f0a77d2bf0c957dc Mon Sep 17 00:00:00 2001
From: Sangmin <sm9171@nate.com>
Date: Tue, 8 Apr 2025 21:37:11 +0900
Subject: [PATCH 3/4] feat: climbing-stairs solution

---
 climbing-stairs/sm9171.java | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 climbing-stairs/sm9171.java

diff --git a/climbing-stairs/sm9171.java b/climbing-stairs/sm9171.java
new file mode 100644
index 000000000..e0c83f206
--- /dev/null
+++ b/climbing-stairs/sm9171.java
@@ -0,0 +1,16 @@
+class Solution {
+    public int climbStairs(int n) {
+        int[] memo = new int[n+1];
+        return recur(n, memo);
+    }
+
+    public static int recur(int n, int[] memo) {
+        if (n < 0) return 0;
+        if (n == 0) return 1;
+
+        if (memo[n] > 0) return memo[n];
+
+        memo[n] = recur(n - 1, memo) + recur(n - 2, memo);
+        return memo[n];
+    }
+}

From 51ed2be526d5128f9058ac0bc49d3e147a35eaa1 Mon Sep 17 00:00:00 2001
From: Sangmin <sm9171@nate.com>
Date: Fri, 11 Apr 2025 23:48:45 +0900
Subject: [PATCH 4/4] feat: product-of-array-except-self solution

---
 product-of-array-except-self/sm9171.java | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 product-of-array-except-self/sm9171.java

diff --git a/product-of-array-except-self/sm9171.java b/product-of-array-except-self/sm9171.java
new file mode 100644
index 000000000..da755cbaa
--- /dev/null
+++ b/product-of-array-except-self/sm9171.java
@@ -0,0 +1,18 @@
+class Solution {
+    public int[] productExceptSelf(int[] nums) {
+        int[] res = new int[nums.length];
+
+        res[0] = 1;
+        for (int i = 1; i < nums.length; i++) {
+            res[i] = res[i - 1] * nums[i - 1];
+        }
+
+        int acc = 1;
+        for (int i = nums.length - 2; i >= 0; i--) {
+            acc *= nums[i + 1];
+            res[i] *= acc;
+        }
+
+        return res;
+    }
+}