【牛客题霸题解】NC7 股票（一次交易）

因为只能买卖一次，我们把每一天都看一遍，如果在当天卖出的话能获得的最大收益是多少，然后再取最大值，就是答案了。
在某一天卖出的最大收益的条件是：在这一天之前价格最便宜的时候买
c++

class Solution {
public:
    int maxProfit(vector<int>& prices) {
            int minn = prices[0];
            int ans = 0;
            for(int i = 0 ; i < prices.size() ; i++)
            {
                    minn = min(minn,prices[i]);
                    ans = max(ans,prices[i]-minn);
            }
            return ans;
    }
};

java

import java.util.*;
public class Solution {
    public int maxProfit (int[] prices) {
        int minn = prices[0];
        int ans = 0;
        for(int i = 0 ; i < prices.length ; i++)
        {
            minn = Math.min(minn,prices[i]);
            ans = Math.max(ans,prices[i]-minn);
        }
        return ans;
    }
}

python

class Solution:
    def maxProfit(self , prices ):
        # write code here
        minn = prices[0];
        ans = 0;
        for i in range(0,len(prices)):
            minn = min(minn,prices[i]);
            ans = max(ans,prices[i]-minn);
        return ans;