121. Best Time to Buy and Sell Stock

Posted 2020-07-28 烁宝宝

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 (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

Example 1:

Input: [7, 1, 5, 3, 6, 4]
Output: 5

max. difference = 6-1 = 5 (not 7-1 = 6, as selling price needsInput: [7, 6, 4, 3, 1]

Output: 0

In this case, no transaction is done, i.e. max profit = 0.
 代码如下：

 1 public class Solution {
 2     public int maxProfit(int[] prices) {
 3         
 4         if(prices.length<=1)
 5         return 0;
 6         int res=0;
 7         int min = Integer.MAX_VALUE, max = Integer.MIN_VALUE;
 8         for (int i = 0; i < prices.length; ++i) {
 9             if (prices[i] < min)
10                 min = prices[i];
11             if (max < prices[i] - min)
12                 max = prices[i] - min;
13         }
14         return max;
15     }
16 }