a2

find-all-numbers-disappeared.py

@@ -0,0 +1,18 @@
+
+# time O(n), space O(1)
+class Solution:
+    def findDisappearedNumbers(self, nums: List[int]) -> List[int]:
+
+        for i in range(len(nums)):
+            idx = abs(nums[i])-1
+            if nums[idx] > 0:
+                nums[idx]*=-1
+
+        res = []
+        for i in range(len(nums)):
+            if nums[i] < 0:
+                nums[i]*=-1
+            else:
+                res.append(i+1)    
+
+        return res

game-of-life.py

@@ -0,0 +1,33 @@
+
+# time O(n*m), space O(1)
+
+class Solution:
+    def gameOfLife(self,board: List[List[int]]):
+
+        for r in range(len(board)):
+            for c in range(len(board[0])):
+                cnt = self.countAlive(board, r,c)
+                if board[r][c] == 1 and (cnt < 2 or cnt > 3):
+                    board[r][c]=2
+                elif board[r][c] == 0 and cnt == 3:
+                    board[r][c]=3
+
+        for r in range(len(board)):
+            for c in range(len(board[0])):
+                if board[r][c] == 2:
+                    board[r][c]=0
+                elif board[r][c] == 3:
+                    board[r][c]=1
+        return board 
+
+
+    def countAlive(self,board, r,c):
+        dirs = [(0,1),(0,-1),(-1,0),(1,0),(-1,-1),(-1,1),(1,-1),(1,1)]
+        cntAlive=0
+        for d in dirs:
+            nr = r+d[0]
+            nc = c+d[1]
+            if (nr >= 0 and nc >= 0 and nr < len(board) and nc < len(board[0])):
+                if board[nr][nc] == 1 or board[nr][nc]==2:
+                    cntAlive+=1
+        return cntAlive

max-and-min.py

@@ -0,0 +1,11 @@
+def findMinMax(arr):
+	mn = float('inf')
+	mx = float('-inf')
+
+	for num in nums:
+		if num < mn: 
+			mn = num 
+		elif mx > num:
+			mx = num 
+
+	return [mn,mx]