# [Best time to buy and sell stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)
###### tags: `Leetcode`, `Easy`, `Sliding Window`

## Approach
* Initialize `maximum_profit` to 0 and `cost_price` to value at 0^th index
* Iterate from 1^st index to the end of the input list
* Check if current value is greater than the `cost_price`
* Calculate profit `current_value - cost_price`
* Calculate maximum of `maximum_profit` and `profit`
* Otherwise set `cost_price` to the value at current index

## Asymptotic Analysis
### Time Complexity: **O(N)**
### Space Complexity: **O(1)**

## Code

from typing import List


class BestTimeToBuyAndSellStock:

    @staticmethod
    def max_profit(prices: List[int]) -> int:
        cost_price, maximum_profit = prices[0], 0
        for index in range(1, len(prices)):
            if prices[index] > cost_price:
                profit = prices[index] - cost_price
                maximum_profit = max(maximum_profit, profit)
            else:
                cost_price = prices[index]
        return maximum_profit


nums = [7, 6, 4, 3, 1]
nums1 = [7, 1, 5, 3, 6, 4]
print(BestTimeToBuyAndSellStock.max_profit(nums))
print(BestTimeToBuyAndSellStock.max_profit(nums1))