63 股票的最大利润

题目

求买卖股票一次能获得的最大利润。例如，输入{9，11，8，5，7，12，16，14}，5的时候买入，16的时候卖出，则能获得最大利润11。

AcWing OJ

C 语言题解

遍历过程中记录最小值min，然后计算当前值与min的差值diff，并更新maxDiff。

int MaxDiff(const int* numbers, unsigned length)
{
	if (numbers == nullptr && length < 2)
		return 0;

	// 假设第一个数是最小值
	int min = numbers[0];
	int maxDiff = numbers[1] - min;

	for (int i = 2; i < length; ++i)
	{
		if (numbers[i - 1] < min)
			min = numbers[i - 1];

		int currentDiff = numbers[i] - min;
		if (currentDiff > maxDiff)
			maxDiff = currentDiff;
	}

	return maxDiff;
}

C++ 题解

class Solution {
public:
    int maxDiff(vector<int>& nums) {
        if(nums.size()==0) return 0;
        int buy=nums[0],diff=0;
        for(auto &x:nums){
            if(x<buy) buy=x;
            if(x-buy>diff) diff=x-buy;
        }
        return diff;
    }
};

python 题解

class Solution(object):
    def maxDiff(self, nums):
        if not nums:
            return 0
        min_ = nums[0]
        max_ = 0
        for i in nums:
            min_ = min(min_,i)
            max_ = max(max_,i - min_)
        return max_