LeetCode in TypeScript
123. Best Time to Buy and Sell Stock III
Hard
You are 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 at most two transactions.
Note: You may not engage in multiple transactions simultaneously (i.e., you must sell the stock before you buy again).
Example 1:
Input: prices = [3,3,5,0,0,3,1,4]
Output: 6
Explanation: Buy on day 4 (price = 0) and sell on day 6 (price = 3), profit = 3-0 = 3. Then buy on day 7 (price = 1) and sell on day 8 (price = 4), profit = 4-1 = 3.
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 = 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: prices = [7,6,4,3,1]
Output: 0
Explanation: In this case, no transaction is done, i.e. max profit = 0.
Example 4:
Input: prices = [1]
Output: 0
Constraints:
1 <= prices.length <= 1050 <= prices[i] <= 105
Solution
function maxProfit(prices: number[]): number {
let firstBuy = Infinity
let secondBuy = Infinity
let firstSell = 0
let secondSell = 0
for (const price of prices) {
firstBuy = Math.min(firstBuy, price)
firstSell = Math.max(firstSell, price - firstBuy)
secondBuy = Math.min(secondBuy, price - firstSell)
secondSell = Math.max(secondSell, price - secondBuy)
}
return secondSell
}
export { maxProfit }