Say you have an array for which the ith element is the price of a given stock on day i.
Design an algorithm to find the maximum profit. You may complete as many transactions as you like (i.e., buy one and sell one share of the stock multiple times).
Note: You may not engage in multiple transactions at the same time (i.e., you must sell the stock before you buy again).
Example 1:
Input: [7,1,5,3,6,4] Output: 7 Explanation: Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 5-1 = 4. Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 6-3 = 3.
Example 2:
Input: [1,2,3,4,5] Output: 4 Explanation: Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 5-1 = 4. Note that you cannot buy on day 1, buy on day 2 and sell them later, as you are engaging multiple transactions at the same time. You must sell before buying again.
Example 3:
Input: [7,6,4,3,1] Output: 0 Explanation: In this case, no transaction is done, i.e. max profit = 0.
解题思路：局部最优解即为全局最优解，每次出现收益就累加收益，贪心。另外困难点可能在于没有很强的能力将这个问题抽象到一个数学模型上，比如发生很多次买卖，当卖出时，同时可以再买入，这一步将问题抽象成了数学问题。
package tt;
import java.util.*;
public class TT {
public static void main(String args[]) {
int prices[]=new int[] {7,5,2,1,3,3,10,14};
Solution test1=new Solution();
System.out.println(test1.maxProfit(prices));
}
}
class Solution {
public int maxProfit(int[] prices) {
int profit=0;
for(int i=0;i<prices.length-1;i++) {
if(prices[i+1]-prices[i]>0) {
profit+=prices[i+1]-prices[i];
}
}
return profit;
}
}
Seen this question in a real interview before?