Mountain Array Peak

You are given a mountain array, which is defined as an array that has a peak element which is greater than its neighbors. Write a function that finds the peak element using binary search. The peak element is defined as an element that is greater than or equal to its neighbors. If the array is [1, 3, 5, 4, 2], the peak is 5. Input is given as an integer array of size n. Output the peak element. Example: Input: 5 1 3 5 4 2 Output: 5