Given an array prices where prices[i] is the price of a given stock on the ith day, find the maximum profit you can achieve.
You may complete as many transactions as you like (i.e., buy one and sell one share of the stock multiple times). However, you must sell the stock before you buy again.
Note: You may not engage in multiple transactions simultaneously (you must sell before you buy again).
Example 1:
Input: prices = [7,1,5,3,6,4]
Output: 7
Explanation: Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 4. Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 3. Total profit = 4 + 3 = 7.
Example 2:
Input: prices = [1,2,3,4,5]
Output: 4
Explanation: Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 4. This is equivalent to buying and selling on consecutive days: (2-1) + (3-2) + (4-3) + (5-4) = 4.
Example 3:
Input: prices = [7,6,4,3,1]
Output: 0
Explanation: Prices only decrease, so no profitable transaction is possible. Maximum profit = 0.
1 <= prices.length <= 3 × 10⁴0 <= prices[i] <= 10⁴