Challenge: Is It a BST Array?

Problem

Given an array of integers, find if it represents a pre-order traversal of a BST.

Input

An integer array.

Output

Return true if the array is the pre-order traversal of a BST, otherwise false.

Sample input

array = {5, 2, 4, 6, 9, 10}

Sample output

true

Let’s look at the illustration below to better understand the problem.