Merge Intervals

Write a function `maxProfit` that takes an array where the `i-th` element is the price of a given stock on day `i`, and returns the maximum profit you can achieve by buying and selling one share of the stock. ## Function Signature ```function maxProfit(prices);``` ### Example 1: > **Input:** `prices = [7,1,5,3,6,4]` \ > **Output:** `5` \ > **Explanation:** Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 6-1 = 5. ### Example 2: > **Input:** `prices = [7,6,4,3,1]` \ > **Output:** `0` \ > **Explanation:** In this case, no transactions are done, i.e. max profit = 0.

Write a function `threeSum` that takes an array of integers and returns all unique triplets that sum up to zero. ## Function Signature ```function threeSum(nums);``` ### Example 1: > **Input:** `nums = [-1, 0, 1, 2, -1, -4]` \ > **Output:** `[[-1, -1, 2], [-1, 0, 1]]` \ > **Explanation:** The triplets that sum up to zero are [-1, -1, 2] and [-1, 0, 1]. ### Example 2: > **Input:** `nums = []` \ > **Output:** `[]` \ > **Explanation:** No triplets can be formed from an empty array. ### Example 3: > **Input:** `nums = [0]` \ > **Output:** `[]` \ > **Explanation:** No triplets can be formed from a single element.

Write a function `productExceptSelf` that takes an array of integers and returns an array such that each element at index `i` is the product of all the numbers in the original array except the one at `i`. ## Function Signature ```function productExceptSelf(nums);``` ### Example 1: > **Input:** `nums = [1, 2, 3, 4]` \ > **Output:** `[24, 12, 8, 6]` \ > **Explanation:** The product of all the numbers except the one at each index is [24, 12, 8, 6]. ### Example 2: > **Input:** `nums = [-1, 1, 0, -3, 3]` \ > **Output:** `[0, 0, 9, 0, 0]` \ > **Explanation:** The product of all the numbers except the one at each index is [0, 0, 9, 0, 0].