best-time-to-buy-sell-stock-121.go

/*
121. Best Time to Buy and Sell Stock
Easy

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
*/

func maxProfit(prices []int) int {
    /* This doesn't work because leet code won't let me import the slices package
        profits := slices.Max(prices) - slices.Min(prices)
        return profits
    */

    minPrice := prices[0]
    profits := 0

    for i := 0; i < len(prices); i++ {
        if prices[i] < minPrice {
             minPrice = prices[i] 
        } else {
            gain := prices[i] - minPrice
            if gain > profits {
                profits = gain
            }
        }
    }

    return profits
}