01 Array -> 11 mountain subarray problem

[Fazeel Usmani]

We are given an array of integers and a range, we need to find whether the subarray which falls in this range has values in the form of a mountain or not. All values of the subarray are said to be in the form of a mountain if either all values are increasing or decreasing or first increasing and then decreasing. More formally a subarray [a1, a2, a3 … aN] is said to be in form of a mountain if there exists an integer K, 1 <= K <= N such that,
a1 <= a2 <= a3 .. <= aK >= a(K+1) >= a(K+2) …. >= aN
You have to process Q queries. In each query you are given two integer L and R, denoting starting and last index of the subarrays respectively.

Example 1:

Input:
N = 8
a[] = {2,3,2,4,4,6,3,2}
Q = 2
Queries = (0,2), (1,3)
Output:
Yes
No
Explanation: For L = 0 and R = 2, a0 = 2,
a1 = 3 and a2 = 2, since they are in the
valid order,answer is Yes.
For L = 1 and R = 3, a1 = 3, a2 = 2 and
a3 = 4, since a1 > a2 and a2 < a4 the
order isn't valid, hence the answer is
No.
Your Task:

Complete the function processQueries() which takes the array, size of array queries and number of queries as parameter. It should return a vector/ArrayList/array (depending upon language cpp/Java/Python) of boolean values, true if the subarray is in mountain form, false otherwise. The driver code will print "Yes" if the returned value is true, otherwise "No".

Expected Time Complexity: O(N + Q).
Expected Auxiliary Space: O(N).

Constraints:
1 <= N, Q <= 105
1 <= a[i] <= 106, for each valid i
0 <= L <= R <= N-1