121. Best Time to Buy and Sell Stock
source: https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
Question
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.
思路
/**
* @param {number[]} prices
* @return {number}
*/
var maxProfit = function (prices) {
let max = -Infinity;
let ret = 0;
for (let i = prices.length - 1; i >= 0; i--) {
const v = max - prices[i];
max = Math.max(max, prices[i]);
if (v > ret) ret = v;
}
return ret;
};