Delete Alternate Nodes

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Time: O(n)

Space: O(1)

Intuition

Delete every alternate node in linked list (keep first, delete second, keep third, etc.).

Algorithm

1Traverse: curr = head. While curr and curr.next: curr.next = curr.next.next. curr = curr.next.

Common Pitfalls

•Simple pointer manipulation. Ensure the "next" link skips the deleted node cleanly.

Delete Alternate Nodes.java

Java

// Approach: Traverse the list and skip every other node by updating next pointers.
// Time: O(n) Space: O(1)
class Solution {
    public void deleteAlt(Node head) {
        Node prev = null;
        Node temp = head;
        int cnt = 0;
        while (temp != null) {
            cnt++;
            if (cnt % 2 == 0) {
                prev.next = temp.next;
            }
            prev = temp;
            temp = temp.next;
        }
    }
}

class Node {
    int data;
    Node next;

    public Node(int data) {
        this.data = data;
    }
}

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