Longest Mountain

Difficulty: 1500 4000 ms 128 MB

two-pointers

A mountain is a contiguous stretch that strictly increases to a peak then strictly decreases, with length ≥ 3. Print the longest mountain's length (0 if none).

Input: the first line has N; the second line has N integers.

Output: the longest mountain length, or 0.

Constraints:

• 1 ≤ N ≤ 10⁵
• |a_i| ≤ 10⁹

Sample Tests

7
2 1 4 7 3 2 5

5

3
1 2 3

0

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