Loop Solution - Best Time to Buy and Sell Stock II

The idea is to update all positive case… whenever lp2 value smaller than lp1 value, update max and being index… the comparison between lp2 - 1 and begin is NOT necessary since the algorithm guarantees b value <= lp2 - 1 value. otherwise begin index should already be updated to lp2 - 1.

public class Solution {
    public int maxProfit(int[] prices) {
        if(prices == null || prices.length < 2){
            return 0;
        }
       
        int begin = 0;
        int end = begin + 1;
        int sum = 0;
        int preEnd = end - 1;
        while(end < prices.length){
            if(prices[end] < prices[preEnd]){
                sum += (prices[preEnd] - prices[begin] > 0 ? prices[preEnd] - prices[begin] : 0);
                begin = end;
            }
            preEnd = end;
            end++;
        }
        if(begin < preEnd){
            sum += prices[preEnd] - prices[begin];
        }
        return sum;
    }
}