class Solution { 
public:
    int maxProfit(vector<int>& prices) {
        int low = INT_MAX, profit = 0;
        for (int price : prices) {
            low = min(low, price); 
            profit = max(profit, price - low);
        }
        return profit;
    }
};

REF：

• https://discuss.leetcode.com/topic/19853/kadane-s-algorithm-since-no-one-has-mentioned-about-this-so-far-in-case-if-interviewer-twists-the-input