Given an integer array arr, return the length of a maximum size turbulent subarray of arr.
A subarray is turbulent if the comparison sign flips between each adjacent pair of elements in the subarray.
More formally, a subarray [arr[i], arr[i + 1], ..., arr[j]] of arr is said to be turbulent if and only if:
i <= k < j:
arr[k] > arr[k + 1] when k is odd, andarr[k] < arr[k + 1] when k is even.i <= k < j:
arr[k] > arr[k + 1] when k is even, andarr[k] < arr[k + 1] when k is odd.
Example 1:
Input: arr = [9,4,2,10,7,8,8,1,9] Output: 5 Explanation: arr[1] > arr[2] < arr[3] > arr[4] < arr[5]
Example 2:
Input: arr = [4,8,12,16] Output: 2
Example 3:
Input: arr = [100] Output: 1
Constraints:
1 <= arr.length <= 4 * 1040 <= arr[i] <= 109struct Solution;
use std::cmp::Ordering::*;
impl Solution {
fn max_turbulence_size(a: Vec<i32>) -> i32 {
let n = a.len();
let mut res = 1;
let mut inc = 1;
let mut dec = 1;
for i in 1..n {
match (a[i] - a[i - 1]).cmp(&0) {
Equal => {
inc = 1;
dec = 1;
}
Less => {
inc = dec + 1;
dec = 1;
}
Greater => {
dec = inc + 1;
inc = 1;
}
}
res = res.max(inc.max(dec));
}
res
}
}
#[test]
fn test() {
let a = vec![9, 4, 2, 10, 7, 8, 8, 1, 9];
let res = 5;
assert_eq!(Solution::max_turbulence_size(a), res);
let a = vec![4, 8, 12, 16];
let res = 2;
assert_eq!(Solution::max_turbulence_size(a), res);
let a = vec![100];
let res = 1;
assert_eq!(Solution::max_turbulence_size(a), res);
let a = vec![100, 100, 100];
let res = 1;
assert_eq!(Solution::max_turbulence_size(a), res);
}