From f7540e3bab53f79c50c70a57f07ebcfd99946f83 Mon Sep 17 00:00:00 2001
From: doh6077 <kimdohee@sheridancollege.ca>
Date: Thu, 13 Nov 2025 00:20:33 -0500
Subject: [PATCH 1/4] two sum solution

---
 two-sum/doh6077.py | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 two-sum/doh6077.py

diff --git a/two-sum/doh6077.py b/two-sum/doh6077.py
new file mode 100644
index 0000000000..333302d8ec
--- /dev/null
+++ b/two-sum/doh6077.py
@@ -0,0 +1,8 @@
+class Solution:
+    def twoSum(self, nums: list[int], target: int) -> list[int]:
+        prevMap = {} # val : index 
+        for i, n in enumerate(nums):
+            diff = target - n 
+            if diff in prevMap:
+                return [prevMap[diff], i]
+            prevMap[n] = i 
\ No newline at end of file

From 3e887656b907eb036600b54d9c739206f9b785c9 Mon Sep 17 00:00:00 2001
From: doh6077 <kimdohee@sheridancollege.ca>
Date: Thu, 13 Nov 2025 00:32:31 -0500
Subject: [PATCH 2/4] two sum solution

---
 two-sum/doh6077.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/two-sum/doh6077.py b/two-sum/doh6077.py
index 333302d8ec..ddc6072e74 100644
--- a/two-sum/doh6077.py
+++ b/two-sum/doh6077.py
@@ -5,4 +5,5 @@ def twoSum(self, nums: list[int], target: int) -> list[int]:
             diff = target - n 
             if diff in prevMap:
                 return [prevMap[diff], i]
-            prevMap[n] = i 
\ No newline at end of file
+            prevMap[n] = i 
+            
\ No newline at end of file

From 3d40dbc43ad0e94af72923e2af6ec2e0b586ef7b Mon Sep 17 00:00:00 2001
From: doh6077 <kimdohee@sheridancollege.ca>
Date: Fri, 14 Nov 2025 11:55:35 -0500
Subject: [PATCH 3/4] contains duplicate solution

---
 contains-duplicate/doh6077.py | 10 ++++++++++
 two-sum/doh6077.py            |  1 -
 2 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 contains-duplicate/doh6077.py

diff --git a/contains-duplicate/doh6077.py b/contains-duplicate/doh6077.py
new file mode 100644
index 0000000000..bc14e47f24
--- /dev/null
+++ b/contains-duplicate/doh6077.py
@@ -0,0 +1,10 @@
+
+# set에 저장하면서 중복 여부 확인하기
+class Solution:
+    def containsDuplicate(self, nums: list[int]) -> bool:
+        hashset = set()
+        for i in nums:
+            if i in hashset:
+                return True
+            hashset.add(i)
+        return False
diff --git a/two-sum/doh6077.py b/two-sum/doh6077.py
index ddc6072e74..2054ef0def 100644
--- a/two-sum/doh6077.py
+++ b/two-sum/doh6077.py
@@ -6,4 +6,3 @@ def twoSum(self, nums: list[int], target: int) -> list[int]:
             if diff in prevMap:
                 return [prevMap[diff], i]
             prevMap[n] = i 
-            
\ No newline at end of file

From 0c700f00c14091d1762446b86bbb1515a891dbf7 Mon Sep 17 00:00:00 2001
From: doh6077 <kimdohee@sheridancollege.ca>
Date: Fri, 14 Nov 2025 18:09:06 -0500
Subject: [PATCH 4/4] Longest Consecutive Sequence Solution

---
 longest-consecutive-sequence/doh6077.py | 34 +++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 longest-consecutive-sequence/doh6077.py

diff --git a/longest-consecutive-sequence/doh6077.py b/longest-consecutive-sequence/doh6077.py
new file mode 100644
index 0000000000..75df1d3fe0
--- /dev/null
+++ b/longest-consecutive-sequence/doh6077.py
@@ -0,0 +1,34 @@
+# 배열을 정렬하고 포인터를 두개 사용
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        if not nums:
+            return 0
+        
+        # sort the given list 
+        sorted_nums = sorted(nums)
+    
+        longest = 1
+        curr = 1
+        
+        l, r = 0, 1
+        
+        while r < len(sorted_nums):
+            # case 1: exactly consecutive (x, x+1)
+            if sorted_nums[r] == sorted_nums[l] + 1:
+                curr += 1
+                longest = max(longest, curr)
+                l += 1
+                r += 1
+            
+            # case 2: duplicate (x, x) → ignore, move right pointer
+            elif sorted_nums[r] == sorted_nums[l]:
+                l += 1
+                r += 1
+            
+            # case 3: gap
+            else:
+                curr = 1
+                l = r
+                r += 1
+        
+        return longest