From 48c6dacf567a04f619a18f8fd2bbd4c9e3a068f1 Mon Sep 17 00:00:00 2001
From: JeonJe <43032391+JeonJe@users.noreply.github.com>
Date: Wed, 12 Aug 2026 22:20:55 +0900
Subject: [PATCH 1/4] reverse bits solution

---
 reverse-bits/JeonJe.java | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 reverse-bits/JeonJe.java

diff --git a/reverse-bits/JeonJe.java b/reverse-bits/JeonJe.java
new file mode 100644
index 0000000000..01a936cb7a
--- /dev/null
+++ b/reverse-bits/JeonJe.java
@@ -0,0 +1,14 @@
+import java.util.*;
+
+// TC: O(1)
+// SC: O(1)
+class Solution {
+    public int reverseBits(int n) {
+        int answer = 0;
+        for (int i = 0; i < 32; i++) {
+            int bitFlag = (n >> i) & 1;
+            answer += (bitFlag << (31 - i));
+        }
+        return answer;
+    }
+}

From 28b445261133bdcc0e3ff0ebb01aa88426666ada Mon Sep 17 00:00:00 2001
From: JeonJe <43032391+JeonJe@users.noreply.github.com>
Date: Wed, 12 Aug 2026 23:09:29 +0900
Subject: [PATCH 2/4] longest repeating character replacement solution

---
 .../JeonJe.java                               | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 longest-repeating-character-replacement/JeonJe.java

diff --git a/longest-repeating-character-replacement/JeonJe.java b/longest-repeating-character-replacement/JeonJe.java
new file mode 100644
index 0000000000..9ae05959ac
--- /dev/null
+++ b/longest-repeating-character-replacement/JeonJe.java
@@ -0,0 +1,29 @@
+import java.util.*;
+
+// TC: O(n)
+// SC: O(1)
+class Solution {
+    public int characterReplacement(String s, int k) {
+        int[] counts = new int[26];
+        int left = 0;
+
+        for (int right = 0; right < s.length(); right++) {
+            counts[toAlphabetIndex(s.charAt(right))]++;
+
+            int windowLength = right - left + 1;
+            int mostFreq = Arrays.stream(counts).max().getAsInt();
+            //바꿀 대상이 k 횟수보다 크면, left을 옮김
+            if (windowLength - mostFreq > k) {
+                counts[toAlphabetIndex(s.charAt(left))]--;
+                left++;
+            }
+        }
+
+        return s.length() - left;
+    }
+
+    private int toAlphabetIndex(char c) {
+        return c - 'A';
+    }
+
+}

From 19e4a09f85cc047ce9ce75e090d8d6c40e2e893e Mon Sep 17 00:00:00 2001
From: JeonJe <43032391+JeonJe@users.noreply.github.com>
Date: Fri, 14 Aug 2026 23:46:00 +0900
Subject: [PATCH 3/4] clone graph solution

---
 clone-graph/JeonJe.java | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 clone-graph/JeonJe.java

diff --git a/clone-graph/JeonJe.java b/clone-graph/JeonJe.java
new file mode 100644
index 0000000000..7cab5fd072
--- /dev/null
+++ b/clone-graph/JeonJe.java
@@ -0,0 +1,28 @@
+import java.util.*;
+
+// TC: O(V + E)
+// SC: O(V)
+class Solution {
+    public Node cloneGraph(Node node) {
+        return deepCopy(node, new HashMap<>());
+    }
+
+    private Node deepCopy(Node node, Map<Node, Node> cloned) {
+        if (node == null) {
+            return null;
+        }
+
+        if (cloned.containsKey(node)) {
+            return cloned.get(node);
+        }
+
+        Node clonedNode = new Node(node.val);
+        cloned.put(node, clonedNode);
+
+        for (Node neighbor : node.neighbors) {
+            clonedNode.neighbors.add(deepCopy(neighbor, cloned));
+        }
+
+        return clonedNode;
+    }
+}

From a191dd67686daab256548c74efde513a07fed8c5 Mon Sep 17 00:00:00 2001
From: JeonJe <43032391+JeonJe@users.noreply.github.com>
Date: Sat, 15 Aug 2026 19:34:15 +0900
Subject: [PATCH 4/4] longest common subsequence solution

---
 longest-common-subsequence/JeonJe.java | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 longest-common-subsequence/JeonJe.java

diff --git a/longest-common-subsequence/JeonJe.java b/longest-common-subsequence/JeonJe.java
new file mode 100644
index 0000000000..d552e1f640
--- /dev/null
+++ b/longest-common-subsequence/JeonJe.java
@@ -0,0 +1,20 @@
+// TC: O(m * n)
+// SC: O(m * n)
+class Solution {
+
+    public int longestCommonSubsequence(String text1, String text2) {
+        int[][] dp = new int[text1.length() + 1][text2.length() + 1];
+
+        for (int i = text1.length() - 1; i >= 0; i--) {
+            for (int j = text2.length() - 1; j >= 0; j--) {
+
+                dp[i][j] = text1.charAt(i) == text2.charAt(j) ?
+                        1 + dp[i + 1][j + 1] :
+                        Math.max(dp[i + 1][j], dp[i][j + 1]);
+
+            }
+        }
+        return dp[0][0];
+    }
+
+}