Package g1301_1400.s1352_product_of_the_last_k_numbers

Class ProductOfNumbers

  • public class ProductOfNumbers
extends Object
    1352 - Product of the Last K Numbers.

    Medium

    Design an algorithm that accepts a stream of integers and retrieves the product of the last k integers of the stream.

    Implement the ProductOfNumbers class:

    • ProductOfNumbers() Initializes the object with an empty stream.
    • void add(int num) Appends the integer num to the stream.
    • int getProduct(int k) Returns the product of the last k numbers in the current list. You can assume that always the current list has at least k numbers.

    The test cases are generated so that, at any time, the product of any contiguous sequence of numbers will fit into a single 32-bit integer without overflowing.

    Example:

    Input [“ProductOfNumbers”,“add”,“add”,“add”,“add”,“add”,“getProduct”,“getProduct”,“getProduct”,“add”,“getProduct”] [ [],[3],[0],[2],[5],[4],[2],[3],[4],[8],[2]]

    Output: [null,null,null,null,null,null,20,40,0,null,32]

    Explanation: ProductOfNumbers productOfNumbers = new ProductOfNumbers(); productOfNumbers.add(3); // [3] productOfNumbers.add(0); // [3,0] productOfNumbers.add(2); // [3,0,2] productOfNumbers.add(5); // [3,0,2,5] productOfNumbers.add(4); // [3,0,2,5,4] productOfNumbers.getProduct(2); // return 20. The product of the last 2 numbers is 5 * 4 = 20 productOfNumbers.getProduct(3); // return 40. The product of the last 3 numbers is 2 * 5 * 4 = 40 productOfNumbers.getProduct(4); // return 0. The product of the last 4 numbers is 0 * 2 * 5 * 4 = 0 productOfNumbers.add(8); // [3,0,2,5,4,8] productOfNumbers.getProduct(2); // return 32. The product of the last 2 numbers is 4 * 8 = 32

    Constraints:

    • 0 <= num <= 100
    • 1 <= k <= 4 * 104
    • At most 4 * 104 calls will be made to add and getProduct.
    • The product of the stream at any point in time will fit in a 32-bit integer.

    • Constructor Detail

      • ProductOfNumbers

        public ProductOfNumbers()

    • Method Detail

      • add

        public void add​(int num)

      • getProduct

        public int getProduct​(int k)