diff --git a/Problem 1- Leetcode80.py b/Problem 1- Leetcode80.py
new file mode 100644
index 00000000..f5266a9b
--- /dev/null
+++ b/Problem 1- Leetcode80.py	
@@ -0,0 +1,18 @@
+#Time Complexity: O(n)
+#Space Complexity: O(1)
+
+class Solution(object):
+    def removeDuplicates(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        slow, fast = 2, 2
+        while fast < len(nums):
+            if nums[fast] != nums[slow - 2]:
+                nums[slow] = nums[fast]
+                slow += 1
+            fast += 1
+        return slow
+
+        
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diff --git a/Problem 2- Leetcode88.py b/Problem 2- Leetcode88.py
new file mode 100644
index 00000000..1cd936db
--- /dev/null
+++ b/Problem 2- Leetcode88.py	
@@ -0,0 +1,28 @@
+#Time Complexity: O(n)
+#Space Complexity: O(1)
+
+class Solution(object):
+    def merge(self, nums1, m, nums2, n):
+        """
+        :type nums1: List[int]
+        :type m: int
+        :type nums2: List[int]
+        :type n: int
+        :rtype: None Do not return anything, modify nums1 in-place instead.
+        """
+        p1, p2, idx = m - 1, n - 1, m + n - 1
+        while p1 >= 0 and p2 >= 0:
+            if nums1[p1] > nums2[p2]:
+                nums1[idx] = nums1[p1]
+                p1 -= 1
+                idx -= 1
+            else:
+                nums1[idx] = nums2[p2]
+                p2 -= 1
+                idx -= 1
+        
+        while p2 >= 0:
+            nums1[idx] = nums2[p2]
+            p2 -= 1
+            idx -= 1
+        
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diff --git a/Problem 3- Leetcode240.py b/Problem 3- Leetcode240.py
new file mode 100644
index 00000000..3e5fc9f4
--- /dev/null
+++ b/Problem 3- Leetcode240.py	
@@ -0,0 +1,20 @@
+#Time Complexity: O(m+n)
+#Space Complexity: O(1)
+
+class Solution(object):
+    def searchMatrix(self, matrix, target):
+        """
+        :type matrix: List[List[int]]
+        :type target: int
+        :rtype: bool
+        """
+        m, n = len(matrix), len(matrix[0])
+        r, c = 0, n - 1
+
+        while r < m and c >= 0:
+            if matrix[r][c] == target: return True
+            elif matrix[r][c] > target: c -= 1
+            else: r += 1
+
+        return False
+        
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