LeetCode Entry

3903. Smallest Stable Index I

04.09.2026 easy 2026 kotlin rust

Index of max suffix - min prefix not less than k

3903. Smallest Stable Index I easy substack youtube

https://dmitrysamoylenko.com/leetcode/

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Problem TLDR

Index of max suffix - min prefix not less than k

Intuition

Small problem, brute force is accepted.

Approach

• don’t forget to inlcude the current position

Complexity

• Time complexity: \(O(n^2)\)

• Space complexity: \(O(n)\)

Code

    fun firstStableIndex(n: IntArray, k: Int) =
    n.indices.find{n.take(it+1).max()-n.drop(it).min()<=k}?:-1

    pub fn first_stable_index(n: Vec<i32>, k: i32) -> i32 {
        (0..n.len()).find(|&i| *n[..=i].iter().max().unwrap() - *n[i..].iter().min().unwrap() <= k).map_or(-1, |i| i as _)
    }