0122.go

// Source: https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii
// Title: Best Time to Buy and Sell Stock II
// Difficulty: Medium
// Author: Mu Yang <http://muyang.pro>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// You are given an integer array prices where prices[i] is the price of a given stock on the ith day.

// On each day, you may decide to buy and/or sell the stock. You can only hold at most one share of the stock at any time. However, you can buy it then immediately sell it on the same day.

// Find and return the maximum profit you can achieve.
//
// Example 1:
//
//   Input: prices = [7,1,5,3,6,4]
//   Output: 7
//   Explanation:
//     Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 5-1 = 4.
//     Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 6-3 = 3.
//     Total profit is 4 + 3 = 7.
//
// Example 2:
//
//   Input: prices = [7,6,4,3,1]
//   Output: 4
//   Explanation:
//     Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 5-1 = 4.
//     Total profit is 4.
//
// Example 3:
//
//   Input: prices = [7,6,4,3,1]
//   Output: 0
//   Explanation: There is no way to make a positive profit, so we never buy the stock to achieve the maximum profit of 0.
//
// Constraints:
//
//   1 <= prices.length <= 13*0^4
//   0 <= prices[i] <= 10^4
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package main

func maxProfit(prices []int) int {
	profit := 0

	prevPrice := prices[0]
	for _, price := range prices[1:] {
		if price > prevPrice {
			profit += price - prevPrice
		}
		prevPrice = price
	}

	return profit
}