121. Best Time to Buy and Sell Stock 简单

Say you have an array for which the ith element is the price of a given stock on day i.

If you were only permitted to complete at most one transaction (i.e., buy one and sell one share of the stock), design an algorithm to find the maximum profit.

Note that you cannot sell a stock before you buy one.

Example 1:

Input: [7,1,5,3,6,4]
Output: 5
Explanation: Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 6-1 = 5.

         Not 7-1 = 6, as selling price needs to be larger than buying price.

Example 2:

Input: [7,6,4,3,1]
Output: 0
Explanation: In this case, no transaction is done, i.e. max profit = 0.

class Solution {
public:
    int maxProfit(vector<int>& prices) {
        int len = prices.size();
        int ans = 0;
        int minn = 1<<30;
        for(int i = 0;i<len;++i){
            minn =  min(minn, prices[i]);
            ans = max(ans , prices[i]-minn);
        }
        return ans ;
    }
};
Last modification:December 29th, 2019 at 03:28 am
如果觉得我的文章对你有用,请随意赞赏