LeetCode:121. 买卖股票的最佳时机（单调栈）

class Solution {
    public int maxProfit(int[] prices) {
        int res=0;
        int MinPrice = Integer.MAX_VALUE;
        int len = prices.length-1;
        for(int i=0;i<=len;i++){
            if(MinPrice>prices[i]){
                MinPrice = prices[i];
            }
            else if((prices[i]-MinPrice)>res){
                res = prices[i]-MinPrice;
            }
        }

        return res;
    }
}