Class Solution


  • public class Solution
    extends Object
    946 - Validate Stack Sequences.

    Medium

    Given two integer arrays pushed and popped each with distinct values, return true if this could have been the result of a sequence of push and pop operations on an initially empty stack, or false otherwise.

    Example 1:

    Input: pushed = [1,2,3,4,5], popped = [4,5,3,2,1]

    Output: true

    Explanation: We might do the following sequence:

    push(1), push(2), push(3), push(4),

    pop() -> 4,

    push(5),

    pop() -> 5, pop() -> 3, pop() -> 2, pop() -> 1

    Example 2:

    Input: pushed = [1,2,3,4,5], popped = [4,3,5,1,2]

    Output: false

    Explanation: 1 cannot be popped before 2.

    Constraints:

    • 1 <= pushed.length <= 1000
    • 0 <= pushed[i] <= 1000
    • All the elements of pushed are unique.
    • popped.length == pushed.length
    • popped is a permutation of pushed.
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • validateStackSequences

        public boolean validateStackSequences​(int[] pushed,
                                              int[] popped)