845. Longest Mountain in Array Medium

1/**
2 * [845] Longest Mountain in Array
3 *
4 * You may recall that an array arr is a mountain array if and only if:
5 * 
6 * 	arr.length >= 3
7 * 	There exists some index i (0-indexed) with 0 < i < arr.length - 1 such that:
8 * 	
9 * 		arr[0] < arr[1] < ... < arr[i - 1] < arr[i]
10 * 		arr[i] > arr[i + 1] > ... > arr[arr.length - 1]
11 * 	
12 * 	
13 * 
14 * Given an integer array arr, return the length of the longest subarray, which is a mountain. Return 0 if there is no mountain subarray.
15 *  
16 * Example 1:
17 * 
18 * Input: arr = [2,1,4,7,3,2,5]
19 * Output: 5
20 * Explanation: The largest mountain is [1,4,7,3,2] which has length 5.
21 * 
22 * Example 2:
23 * 
24 * Input: arr = [2,2,2]
25 * Output: 0
26 * Explanation: There is no mountain.
27 * 
28 *  
29 * Constraints:
30 * 
31 * 	1 <= arr.length <= 10^4
32 * 	0 <= arr[i] <= 10^4
33 * 
34 *  
35 * Follow up:
36 * 
37 * 	Can you solve it using only one pass?
38 * 	Can you solve it in O(1) space?
39 * 
40 */
41pub struct Solution {}
42
43// problem: https://leetcode.com/problems/longest-mountain-in-array/
44// discuss: https://leetcode.com/problems/longest-mountain-in-array/discuss/?currentPage=1&orderBy=most_votes&query=
45
46// submission codes start here
47
48impl Solution {
49    pub fn longest_mountain(arr: Vec<i32>) -> i32 {
50        0
51    }
52}
53
54// submission codes end
55
56#[cfg(test)]
57mod tests {
58    use super::*;
59
60    #[test]
61    fn test_845() {
62    }
63}
64