LeetCode Entry

141. Linked List Cycle

06.03.2024 easy 2024 kotlin

Detect cycle

141. Linked List Cycle easy blog post substack youtube image.png

Join me on Telegram

https://t.me/leetcode_daily_unstoppable/530

Problem TLDR

Detect cycle #easy

Intuition

Use two pointers, fast and slow, they will meet sometime.

Approach

No Rust in the templates provided, sorry.

Complexity

  • Time complexity: \(O(n)\)

  • Space complexity: \(O(1)\)

Code


    fun hasCycle(h: ListNode?, f: ListNode? = h?.next): Boolean =
    f != null && (h == f || hasCycle(h?.next, f?.next?.next))



    bool hasCycle(ListNode *s) {
        auto f = s;
        while (f && f->next) {
            s = s->next; f = f->next->next;
            if (s == f) return true;
        }
        return false;
    }