Package g1401_1500.s1441_build_an_array_with_stack_operations

Class Solution

  • public class Solution
extends Object
    1441 - Build an Array With Stack Operations.

    Easy

    You are given an array target and an integer n.

    In each iteration, you will read a number from list = [1, 2, 3, ..., n].

    Build the target array using the following operations:

    • "Push": Reads a new element from the beginning list, and pushes it in the array.
    • "Pop": Deletes the last element of the array.
    • If the target array is already built, stop reading more elements.

    Return a list of the operations needed to build target. The test cases are generated so that the answer is unique.

    Example 1:

    Input: target = [1,3], n = 3

    Output: [“Push”,“Push”,“Pop”,“Push”]

    Explanation:

    Read number 1 and automatically push in the array -> [1]

    Read number 2 and automatically push in the array then Pop it -> [1]

    Read number 3 and automatically push in the array -> [1,3]

    Example 2:

    Input: target = [1,2,3], n = 3

    Output: [“Push”,“Push”,“Push”]

    Example 3:

    Input: target = [1,2], n = 4

    Output: [“Push”,“Push”]

    Explanation: You only need to read the first 2 numbers and stop.

    Constraints:

    • 1 <= target.length <= 100
    • 1 <= n <= 100
    • 1 <= target[i] <= n
    • target is strictly increasing.

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • buildArray

        public List<String> buildArray​(int[] target,
                               int n)