Best_Time_to_Buy_and_Sell_Stock_I

题目描述：

  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.
   (
       假设你有一个数组，其中i元素是给定股票在第i天的价格。
       如果你只允许最多完成一个交易（即买入一个股票，卖出一份股票）
       设计一个最大利润的算法。
   )
   Example 1:
   Input: [7, 1, 5, 3, 6, 4]
   Output: 5
   max. difference = 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
   In this case, no transaction is done, i.e. max profit = 0.

public class Solution {    public  int maxProfit(int prices[])    {        int local = 0;          int global = 0;          for(int i=0;i<prices.length-1;i++)          {              local = Math.max(local+prices[i+1]-prices[i],0);              global = Math.max(local, global);          }          return global;      }        public static void main(String[] args) {int price[]={7, 1, 5, 3, 6, 4};System.out.println(maxProfit(price));}}