Best Time to Buy and Sell Stock II

问题：

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).

思路：

上升过程中累加即可

我的代码：

public class Solution {
    public int maxProfit(int[] prices) {
        int len = prices.length ;
        if(len <= 1)
            return 0 ;
        int profit = 0 ;
        for(int i = 0 ; i < len - 1 ; i ++)
        {
            if(prices[i+1] > prices[i])
                profit += prices[i+1] - prices[i] ;
        }
        return profit ;
    }
}

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别人代码：

public class Solution {
    public int maxProfit(int[] prices) {
        int profit = 0;
        for (int i = 0; i < prices.length - 1; i++) {
            int diff = prices[i+1] - prices[i];
            if (diff > 0) {
                profit += diff;
            }
        }
        return profit;
    }
}

View Code

学习之处：

diff的变量命名不错

if(null==stocks || stocks.length==0) return 0;
int maxProfit = 0 ;
int cur = stocks[0];
for(int stock : stocks){
if(stock > cur) maxProfit += (stock-cur);
else cur = stock;
}
return maxProfit;