MaxProfit.java

class Solution {
    public int solution(int[] A) {
        int len = A.length;
        if (len == 0) return 0;
        int min = A[0];
        int profits = 0;
        for (int i = 1; i < len; i++) {
            int price = A[i];
            if (price < min) {
                min = price;
            } else {
                int diff = price - min;
                if (diff > profits) {
                    profits = diff;
                }
            }
        }
        return profits;
    }
}