FastPrep
Problem · Linked List

Process Queries on Cart

● EasyAmazonNEW GRADOA
See Amazon hiring insights

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:

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

    Examples
    01 · Example 1
    items = [1, 2, 1, 2, 1]
query = [-1, -1, 3, 4, -3]
return = [2, 2, 1, 4]

    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.

    02 · Example 2
    items = [5, 1, 2, 2, 4, 6]
query = [1, -2, -1, -1]
return = [5, 2, 4, 6]

    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.

    Constraints
    • 1 <= n, q <= 2 * 10^5
    • 1 <= items[i] <= 10^9
    • -10^9 <= query[i] <= 10^9
    • It is guaranteed that query[i] != 0
    More Amazon problems
    drafts saved locally
    public int[] processQueriesOnCart(int[] items, int[] query) {
  // write your code here
}
    items[1, 2, 1, 2, 1]
    query[-1, -1, 3, 4, -3]
    expected[2, 2, 1, 4]
    sign in to submit