LeetCode Entry

3350. Adjacent Increasing Subarrays Detection II

15.10.2025 medium 2025 kotlin rust

Max k of adjucent increasing k-windows

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Problem TLDR

Max k of adjucent increasing k-windows #medium #counting

Intuition

In a single iteration, count of increasing numbers. Drop on non-increasing. Compare with previous.

Approach

• can use chunk_by and windows in Rust

Complexity

• Time complexity: \(O(n)\)

• Space complexity: \(O(1)\), or O(n)

Code

// 870ms
    fun maxIncreasingSubarrays(n: List<Int>): Int {
        var a = 0; var b = 0; var p = 0
        return n.maxOf { n ->
            if (n > p) ++a else { b = a; a = 1 }
            p = n; max(a/2, min(a, b))
        }
    }

// 26ms
    pub fn max_increasing_subarrays(n: Vec<i32>) -> i32 {
        once(0).chain(n.chunk_by(|a,b| a < b).map(|c| c.len() as i32)).collect::<Vec<_>>()
        .windows(2).map(|c| c[0].min(c[1]).max(c[1]/2)).max().unwrap()
    }