题目链接

class Solution {
    public int maxProfit(int[] prices) {
        if(prices.length <= 1)
            return 0;
        int low = prices[0],res = 0;
        for(int i=1;i<prices.length;i++){
            low = Math.min(low,prices[i]);
            res = Math.max(res,prices[i] - low);
        }
        return res;
    }
}