3652 - Best Time to Buy and Sell Stock using Strategy.

Medium

You are given two integer arrays prices and strategy, where:

• prices[i] is the price of a given stock on the <code>i^th</code> day.

• strategy[i] represents a trading action on the <code>i^th</code> day, where:

You are also given an even integer k, and may perform at most one modification to strategy. A modification consists of:

• Selecting exactly k consecutive elements in strategy.

• Set the first k / 2 elements to 0 (hold).

• Set the last k / 2 elements to 1 (sell).

The profit is defined as the sum of strategy[i] * prices[i] across all days.

Return the maximum possible profit you can achieve.

Note: There are no constraints on budget or stock ownership, so all buy and sell operations are feasible regardless of past actions.

Example 1:

Input: prices = 4,2,8, strategy = -1,0,1, k = 2

Output: 10

Explanation:

Thus, the maximum possible profit is 10, which is achieved by modifying the subarray [0, 1].

Example 2:

Input: prices = 5,4,3, strategy = 1,1,0, k = 2

Output: 9

Explanation:

Thus, the maximum possible profit is 9, which is achieved without any modification.

Constraints:

• <code>2 <= prices.length == strategy.length <= 10⁵</code>

• <code>1 <= pricesi<= 10⁵</code>

• -1 <= strategy[i] <= 1

• 2 <= k <= prices.length

• k is even