2018-09-02 08:35:10 +00:00
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# [121. Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/)
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# 思路
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题目的意思就是求数组prices中，prices[i]-prices[j]的最大值,其中i > j。
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因此prices[j]肯定是prices[i]之前的元素中最小的那一个，所以从前往后遍历，并用min_price记录当前位置前的元素中最小的一个。
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另外注意单独判断空数组的情况。
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# C++
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2019-09-13 15:08:41 +00:00
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``` C++
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2018-09-02 08:35:10 +00:00
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class Solution {
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public:
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int maxProfit(vector<int>& prices) {
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if(prices.size() == 0) return 0;
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int max_profit = 0, min_price = prices[0];
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for(int i = 1; i < prices.size(); i++){
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if(prices[i] - min_price > max_profit) max_profit = prices[i] - min_price;
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if(min_price > prices[i]) min_price = prices[i];
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}
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return max_profit;
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}
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};
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```
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