# Best Time to Buy and Sell Stock Easy Leetcode Problem Brute Force to Optimized

# Problem

Best Time to Buy and Sell Stock — LeetCode

You are given an array `prices`

where `prices[i]`

is the price of a given stock on the `ith`

day.

You want to maximize your profit by choosing a **single day** to buy one stock and choosing a **different day in the future** to sell that stock.

Return *the maximum profit you can achieve from this transaction*. If you cannot achieve any profit, return `0`

.

**Example 1:**

**Input:** prices = [7,1,5,3,6,4] **Output:** 5 **Explanation:** Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 6–1 = 5. Note that buying on day 2 and selling on day 1 is not allowed because you must buy before you sell.

**Example 2:**

**Input:** prices = [7,6,4,3,1] **Output:** 0 **Explanation:** In this case, no transactions are done and the max profit = 0.

**Constraints:**

`1 <= prices.length <= 105`

`0 <= prices[i] <= 104`

# Brute Force to Optimized

`# prices = [7,1,5,3,6,4]`

2min_ = prices[0]

profit = 0

for p in prices[1:]:

profit = max(profit, p-min_)

min_ = min(min_, p)

return profit