Completed Problem 2, leetcode 289 and 448

Problem1-Leetcode448.py

@@ -0,0 +1,21 @@
+#Time Complexity: O(n)
+#Space Complexity: O(1)
+
+class Solution(object):
+    def findDisappearedNumbers(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[int]
+        """
+        result = []
+        for i in range(len(nums)):
+            index = abs(nums[i]) - 1
+            if nums[index] > 0:
+                nums[index] *= -1
+
+        for i in range(len(nums)):
+            if nums[i] > 0:
+                result.append(i + 1)
+
+        return result
+

Problem2-MinAndMaxOfArray.py

@@ -0,0 +1,31 @@
+#Time Complexity: O(n)
+#Space Complexity: O(1)
+
+class Solution:
+
+    def findMinAndMax(self, nums):
+        n = len(nums)
+        i = 0
+
+        if n % 2 == 0:
+            if nums[0] < nums[1]:
+                minimum = nums[0]
+                maximum = nums[1]
+            else:
+                minimum = nums[1]
+                maximum = nums[0]
+            i = 2
+        else:
+            minimum = maximum = nums[0]
+            i = 1
+
+        while i < n - 1:
+            if nums[i] < nums[i + 1]:
+                minimum = min(minimum, nums[i])
+                maximum = max(maximum, nums[i + 1])
+            else:
+                minimum = min(minimum, nums[i + 1])
+                maximum = max(maximum, nums[i])
+            i += 2
+
+        return [minimum, maximum]

Problem3-Leetcode289.py

@@ -0,0 +1,36 @@
+#Time Complexity: O(m*n)
+#Space Complexity: O(1)
+
+class Solution(object):
+    def gameOfLife(self, board):
+        """
+        :type board: List[List[int]]
+        :rtype: None Do not return anything, modify board in-place instead.
+        """
+        dirs = [(-1,-1), (-1,0), (-1,1), (0,-1), (0,1), (1,-1), (1,0), (1,1)]
+        m, n = len(board), len(board[0])
+
+        def getCount(i, j):
+            count = 0
+            for dx, dy in dirs:
+                r, c = i + dx, j + dy
+                if 0 <= r < m and 0 <= c < n:
+                    if board[r][c] == 1 or board[r][c] == 2:
+                        count += 1
+            return count
+
+        for i in range(m):
+            for j in range(n):
+                cnt = getCount(i, j)
+                if board[i][j] == 0 and cnt == 3:
+                    board[i][j] = 3
+                elif board[i][j] == 1 and (cnt < 2 or cnt > 3):
+                    board[i][j] = 2
+
+        for i in range(m):
+            for j in range(n):
+                if board[i][j] == 2:
+                    board[i][j] = 0
+                elif board[i][j] == 3:
+                    board[i][j] = 1
+