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

洪健翔 Hung, Chien-hsiang
2 min readMay 24, 2023

Best Time to Buy and Sell Stock Easy Leetcode Problem Brute Force to Optimized — Hung, Chien-Hsiang | Blog (chienhsiang-hung.github.io)

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

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