From d75626834c9d743d2f39d9c66e91520a6eb19ece Mon Sep 17 00:00:00 2001
From: donghyeon95 <ubuntu@DESKTOP-V37DRE1>
Date: Sun, 29 Dec 2024 23:43:00 +0900
Subject: [PATCH 1/3] feat: Merge Two Sorted Lists #224

---
 merge-two-sorted-lists/donghyeon95.java | 36 +++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 merge-two-sorted-lists/donghyeon95.java

diff --git a/merge-two-sorted-lists/donghyeon95.java b/merge-two-sorted-lists/donghyeon95.java
new file mode 100644
index 000000000..99bc24013
--- /dev/null
+++ b/merge-two-sorted-lists/donghyeon95.java
@@ -0,0 +1,36 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+	public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
+		// O(N)
+		// 2포인터로 지나가용 하면 되는 문제
+		ListNode result = new ListNode();
+		ListNode nowNode = result;
+
+
+		while (list1!=null || list2!=null) {
+			int first = list1==null? 101: list1.val;
+			int second = list2==null? 101: list2.val;
+
+			if (first < second) {
+				nowNode.next = new ListNode(first);
+				nowNode = nowNode.next;
+				list1 = list1.next;
+			} else {
+				nowNode.next = new ListNode(second);
+				nowNode = nowNode.next;
+				list2 = list2.next;
+			}
+		}
+
+		return result.next;
+	}
+}
\ No newline at end of file

From dd5d98d2c82fad2e5e4c44f22da31f95bc577f1e Mon Sep 17 00:00:00 2001
From: donghyeon95 <ubuntu@DESKTOP-V37DRE1>
Date: Sun, 29 Dec 2024 23:43:22 +0900
Subject: [PATCH 2/3] =?UTF-8?q?=EA=B0=9C=ED=96=89=20=EB=AC=B8=EC=9E=90=20?=
 =?UTF-8?q?=EC=B6=94=EA=B0=80?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 merge-two-sorted-lists/donghyeon95.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/merge-two-sorted-lists/donghyeon95.java b/merge-two-sorted-lists/donghyeon95.java
index 99bc24013..e4f43c128 100644
--- a/merge-two-sorted-lists/donghyeon95.java
+++ b/merge-two-sorted-lists/donghyeon95.java
@@ -33,4 +33,5 @@ public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
 
 		return result.next;
 	}
-}
\ No newline at end of file
+}
+

From c48048d6b9d610ba400280ac730f9787e401cff2 Mon Sep 17 00:00:00 2001
From: donghyeon95 <ubuntu@DESKTOP-V37DRE1>
Date: Sun, 29 Dec 2024 23:55:50 +0900
Subject: [PATCH 3/3] feat: Missing Number #235

---
 missing-number/donghyeon95.java | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 missing-number/donghyeon95.java

diff --git a/missing-number/donghyeon95.java b/missing-number/donghyeon95.java
new file mode 100644
index 000000000..03985af52
--- /dev/null
+++ b/missing-number/donghyeon95.java
@@ -0,0 +1,19 @@
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+// O(N)
+class Solution {
+	public int missingNumber(int[] nums) {
+		Set<Integer> numSet = Arrays.stream(nums).boxed().collect(Collectors.toSet());
+
+		for (int i=0; i<nums.length; i++) {
+			if (!numSet.contains(i)) return i;
+		}
+
+		return nums.length;
+	}
+}
+