121.best-time-to-buy-and-sell-stock.1.go

/*
 * @lc app=leetcode id=121 lang=golang
 *
 * [121] Best Time to Buy and Sell Stock
 *
 * https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/
 *
 * algorithms
 * Easy (46.64%)
 * Total Accepted:    472.6K
 * Total Submissions: 1M
 * Testcase Example:  '[7,1,5,3,6,4]'
 *
 * Say you have an array for which the i^th element is the price of a given
 * stock on day i.
 *
 * If you were only permitted to complete at most one transaction (i.e., buy
 * one and sell one share of the stock), design an algorithm to find the
 * maximum profit.
 *
 * Note that you cannot sell a stock before you buy one.
 *
 * Example 1:
 *
 *
 * Input: [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.
 * Not 7-1 = 6, as selling price needs to be larger than buying price.
 *
 *
 * Example 2:
 *
 *
 * Input: [7,6,4,3,1]
 * Output: 0
 * Explanation: In this case, no transaction is done, i.e. max profit = 0.
 *
 *
 */
func maxProfit(prices []int) int {
	l := len(prices)
	best := 0
	for i := 0; i < l; i++ {
		for j := i; j < l; j++ {
			profit := prices[j] - prices[i]
			if profit > best {
				best = profit
			}
		}
	}

	return best
}