diff --git a/leetocde_289.py b/leetocde_289.py
new file mode 100644
index 00000000..4dbc0e3f
--- /dev/null
+++ b/leetocde_289.py
@@ -0,0 +1,29 @@
+class Solution:
+    def gameOfLife(self, board: List[List[int]]) -> None:
+        m = len(board)
+        n = len(board[0])
+
+        directions = [(-1,-1),(-1,0),(-1,1),
+                      (0,-1),        (0,1),
+                      (1,-1),(1,0),(1,1)]
+
+        for i in range(m):
+            for j in range(n):
+                live = 0
+                for dx, dy in directions:
+                    x = i + dx
+                    y = j + dy
+                    if 0 <= x < m and 0 <= y < n and abs(board[x][y]) == 1:
+                        live += 1
+
+                if board[i][j] == 1 and (live < 2 or live > 3):
+                    board[i][j] = -1   # live → dead
+                if board[i][j] == 0 and live == 3:
+                    board[i][j] = 2    # dead → live
+
+        for i in range(m):
+            for j in range(n):
+                if board[i][j] > 0:
+                    board[i][j] = 1
+                else:
+                    board[i][j] = 0
\ No newline at end of file
diff --git a/leetocde_448.py b/leetocde_448.py
new file mode 100644
index 00000000..91edce3c
--- /dev/null
+++ b/leetocde_448.py
@@ -0,0 +1,13 @@
+class Solution:
+    def findDisappearedNumbers(self, nums: List[int]) -> List[int]:
+        for i in range(len(nums)):
+            idx = abs(nums[i]) - 1
+            nums[idx] = -abs(nums[idx])
+
+        res = []
+        for i in range(len(nums)):
+            if nums[i] > 0:
+                res.append(i + 1)
+
+        return res
+        
\ No newline at end of file