LeetCode Entry

1606. Find Servers That Handled Most Number of Requests

09.11.2026 hard 2026 kotlin rust

Most frequent servers handling requests by picking from i%k.. cycle range

1606. Find Servers That Handled Most Number of Requests hard substack youtube

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Problem TLDR

Most frequent servers handling requests by picking from i%k.. cycle range

Intuition

Simulate the process. Maintain the busy servers by sorted time and free servers by sorted indices. Split free into head and tail.

Approach

• TreeSet ceiling(x) in kotlin and BTreeSet.range(x..).next() give the exactly equal or greater value
• Rust itertools: max_set_by_key

Complexity

• Time complexity: \(O(nlogn)\)

• Space complexity: \(O(n)\)

Code

    fun busiestServers(k: Int, a: IntArray, l: IntArray)=run{
        val q = PriorityQueue<Long>(); val s = TreeSet<Int>();s+=0..<k; val f = IntArray(k)
        for (i in a.indices) {
            while (q.any() && q.peek() / k <= a[i]) s += (q.poll() % k).toInt()
            val j = s.ceiling(i % k) ?: s.firstOrNull() ?: continue
            s -= j; f[j]++; q += (a[i] + l[i]) * 1L * k + j
        }
        val m = f.max(); f.indices.filter { f[it] == m }
    }

    pub fn busiest_servers(k: i32, a: Vec<i32>, l: Vec<i32>) -> Vec<i32> {
        let (k, mut q, mut s, mut f) = (k as i64, BinaryHeap::<i64>::new(), BTreeSet::from_iter(0..k as i64), vec![0; k as usize]);
        for i in 0..a.len() {
            while q.peek().map_or(false, |&t| -t / k <= a[i] as i64) { s.insert(-q.pop().unwrap() % k); }
            if let Some(&j) = s.range(i as i64 % k..).next().or(s.first()) {
                s.remove(&j); f[j as usize] += 1; q.push(-((a[i] + l[i]) as i64 * k + j));
            }
        }
        (0..k as i32).max_set_by_key(|&i| f[i as usize])
    }