Best Time to Buy and Sell Stock II Java

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).

Have you been asked this question in an interview? 

This problem is look like complicated first, but if we read question carefully

    we will notice that

    Base on the constrain that you must sell the stock before you buy again

    that means The number of  transaction will less than n (n is total transaction days)

    Thus, as long as we add all the difference between two days' greater than 0,

    then, the result will be maxProfit

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