#C4855. Mountain Sequence
Mountain Sequence
Mountain Sequence
You are given an array of integers. Your task is to determine whether the array forms a mountain sequence.
A valid mountain sequence must satisfy the following conditions:
- The array length is at least 3.
- There exists an index \( i \) (1 \( \leq i \leq n-2 \)) such that:
- The subarray \( a_0, a_1, \dots, a_i \) is strictly increasing.
- The subarray \( a_i, a_{i+1}, \dots, a_{n-1} \) is strictly decreasing.
- The peak cannot be the first or the last element.
Input is read from standard input and the result must be printed to standard output as either True
or False
.
inputFormat
The first line contains a single integer \( n \) which denotes the number of elements in the array. The second line contains \( n \) space-separated integers representing the array elements.
outputFormat
Output a single line: True
if the array forms a mountain sequence, otherwise False
.
5
2 5 7 3 1
True