Best Time to Buy and Sell Stock Java

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

If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

Have you been asked this question in an interview?  

 Naive Approach: brute force find max Profit Time: O(N^2)
    Better idea:
    The Classical DP problem again, similar idea as Maximum Subarray problem
    Approach: Optimize Local and Global solution.
    Local: Current Max profit => local[i+1]=Max(local[i]+prices[i+1]-prices[i], 0)
        that we have make profit if profit>0, otherwise, not profit made
    Global: Max profit after i days => global=(local[i+1],global)
    Time: O(N)  Space O(1)

public class Solution {
    public int maxProfit(int[] prices) {
         //check for special case
        if(prices.length==0){
            return 0;
        }
        int local=0;
        int global=0;
        for(int i=0;i<prices.length-1;i++){
              //optimize local
            local=Math.max(local+prices[i+1]-prices[i],0);
            //optimize global
            global=Math.max(global,local);
        }

        return global;
    }
}