diff --git a/buyAndSellStock.py b/buyAndSellStock.py
new file mode 100644
index 0000000..3d9d784
--- /dev/null
+++ b/buyAndSellStock.py
@@ -0,0 +1,11 @@
+# TC: O(n)
+# SC: O(1)
+class Solution:
+    def maxProfit(self, prices: List[int]) -> int:
+        profit=0
+        n=len(prices)
+        for i in range(n-1):
+            if prices[i]<prices[i+1]:
+                profit+=prices[i+1]-prices[i]
+        
+        return profit
\ No newline at end of file
diff --git a/peekingIterator.py b/peekingIterator.py
new file mode 100644
index 0000000..9d5513c
--- /dev/null
+++ b/peekingIterator.py
@@ -0,0 +1,64 @@
+# Below is the interface for Iterator, which is already defined for you.
+#
+# class Iterator:
+#     def __init__(self, nums):
+#         """
+#         Initializes an iterator object to the beginning of a list.
+#         :type nums: List[int]
+#         """
+#
+#     def hasNext(self):
+#         """
+#         Returns true if the iteration has more elements.
+#         :rtype: bool
+#         """
+#
+#     def next(self):
+#         """
+#         Returns the next element in the iteration.
+#         :rtype: int
+#         """
+
+class PeekingIterator:
+    def __init__(self, iterator):
+        """
+        Initialize your data structure here.
+        :type iterator: Iterator
+        """
+        self.iterator=iterator
+        self.nextEle=self.iterator.next() if self.iterator.hasNext() else None
+    
+    def advance(self):
+        self.nextEle=self.iterator.next() if self.iterator.hasNext() else None
+        
+    def peek(self):
+        """
+        Returns the next element in the iteration without advancing the iterator.
+        :rtype: int
+        """
+        return self.nextEle
+        
+
+    def next(self):
+        """
+        :rtype: int
+        """
+        temp=self.nextEle
+        self.advance()
+        return temp
+        
+
+    def hasNext(self):
+        """
+        :rtype: bool
+        """
+        if self.nextEle:
+            return True
+        return False
+        
+
+# Your PeekingIterator object will be instantiated and called as such:
+# iter = PeekingIterator(Iterator(nums))
+# while iter.hasNext():
+#     val = iter.peek()   # Get the next element but not advance the iterator.
+#     iter.next()         # Should return the same value as [val].
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