Peak of a Mountain List

nums is a mountain: its values are all different and strictly increase up to a peak, then strictly decrease (the peak can be the first or the last value, for example [1, 2, 3] or [3, 2, 1]). Return the index of the peak, which is also the position of the largest value.

Examples

Example 1

Input:

mountain_peak([1, 3, 5, 4, 2])

Output:

2

Example 2

Input:

mountain_peak([1, 2, 3])

Output:

2

Constraints

• 1 <= len(nums) <= 2 * 10**5
• Strictly increasing to one peak, then strictly decreasing.
• 0 <= nums[i] <= 10**9
• The big tests count how many values your code reads from the list (the limit is stated in the failure message). Reading every value, or using in, .index, .count, min or sorted on the whole list, fails them.