Description
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 (i.e., buy one and sell one share of the stock multiple times). 可以多次买入卖出
Note: You may not engage in multiple transactions at the same time (i.e., you must sell the stock before you buy again). 买之前要先卖掉
Example
Example 1:
Input: [7,1,5,3,6,4]
Output: 7
Explanation: Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 5-1 = 4.
Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 6-3 = 3.
.
Example 2:
Input: [1,2,3,4,5]
Output: 4
Explanation: Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 5-1 = 4.
Note that you cannot buy on day 1, buy on day 2 and sell them later, as you are
engaging multiple transactions at the same time. You must sell before buying again.
.
Example 3:
Input: [7,6,4,3,1]
Output: 0
Explanation: In this case, no transaction is done, i.e. max profit = 0.
Code
class Solution {
public int maxProfit(int[] prices) {
//买入之前必需要卖掉，所以只要依次比较即可，后面数比前一次买入高，就可以卖。卖掉
int total = 0;
for (int i=0; i< prices.length-1; i++) {
if (prices[i+1]>prices[i])
total += (prices[i+1]-prices[i]);
}
return total;
}
}