Process Queries on Cart

As an aspiring developer at Amazon, you are building a prototype for a cart management service. There is an array of integers, items, that represents the item ids present in the cart initially. Given an array of q integers, query, your service must perform as follows. Each integer is an item id to be added to or removed from the cart. If the query integer is positive, add the integer representing an item id to the back of the cart. If the integer is negative, remove the first occurrence of the integer from the cart. Report an array that represents the final cart after processing all the queries. It is guaranteed that the final cart is non-empty and the integers in the integer Function Description Complete the function processQueriesOnCart in the editor below. processQueriesOnCart has the following parameters:

• int items[n]: items initially in the cart
• int query[q]: items to add or remove

Constraints

• 1 ≤ n, q ≤ 2 * 10⁵
• 1 ≤ items[i] ≤ 10⁹
• -10⁹ ≤ query[i] ≤ 10⁹
• It is guaranteed that query[i] ≠ 0

Example 1

Input:

items = [1, 2, 1, 2, 1]
query = [-1, -1, 3, 4, -3]

Output:

[2, 2, 1, 4]

Explanation: Initially, there are n = 5 items in the cart represented as cart = [1,2,1,2,1] and queries = [-1,-1,3,4,-3] QueryTaskCart -1Delete first 1 from cart[2,1,2,1] -1Delete first 1 from cart[2,2,1] 3Append 3 to cart[2,2,1,3] 4Append 4 to cart[2,2,1,3,4] -3Delete first 3 from cart[2,2,1,4] Report [2,2,1,4] as the final cart.

Example 2

Input:

items = [5, 1, 2, 2, 4, 6]
query = [1, -2, -1, -1]

Output:

[5, 2, 4, 6]

Explanation: items = [5, 1, 2, 2, 4, 6] queries = [1, -2, -1, -1] QueryTaskCart 1Append 1 to cart[5, 1, 2, 2, 4, 6, 1] -2Delete first 2 from cart[5, 1, 2, 4, 6, 1] -1Delete first 1 from cart[5, 2, 4, 6, 1] -1Delete first 1 from cart[5, 2, 4, 6] Report [5, 2, 4, 6] as the final cart.