面试经典 150 题 （八）

将所有的递增段的增加值叠加起来

class Solution {
    public int maxProfit(int[] prices) {
        if (prices.length <= 1){
            return 0;
        }
        int pre = 0;
        int p = 1;
        int maxPro = 0;
        int start = 0;
        boolean flag = false;   //标志当前是否是递增
        while(p < prices.length){
            if(prices[pre] < prices[p]){
                if (flag == false){
                    flag = true;
                    start = pre;
                }
            }else{
                if (flag == true){
                    flag = false;
                    maxPro = maxPro +  (prices[pre] - prices[start]);
                }
            }
            pre++;
            p++;
        }
        if (flag){
            maxPro = maxPro + (prices[pre] - prices[start]);
        }
        return maxPro;
    }
}