add solution for best time to buy and sell stock problem

Author: jamiebase

best-time-to-buy-and-sell-stock/gcount85.py

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+"""
+# Approach
+지금까지의 최저 가격을 갱신함과 동시에 최선의 이익도 업데이트합니다.
+
+# Complexity
+- Time complexity: O(N)
+
+- Space complexity: O(1)
+"""
+
+
+class Solution:
+    def maxProfit(self, prices: list[int]) -> int:
+        min_price = float("inf")
+        answer = 0
+
+        for price in prices:
+            min_price = min(min_price, price)
+            answer = max(answer, price - min_price)
+
+        return answer