[LeetCode] Best Time to Buy and Sell Stock II

Say you have an array for which the ith element is the price of a given stock on day i.

Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

更上一题不同的是，这次是想交易多少次就交易多少次，不过每次只能进行一次交易，即交易不能重叠。

采用贪心法，如果有赚头就执行一次交易，这样就可以累计所有的价格增益。

/**
 * @param {number[]} prices
 * @return {number}
 */
var maxProfit = function(prices) {
    var prev = prices[0];
    var profit = 0;

    prices.forEach(function(now) {
        if (now > prev){
            profit += now - prev;
        }
        prev = now;
    });

    return profit;
};