Middle of Linked List (ladder)

Description

Find the middle node of a linked list.

Example:
Given 1->2->3, return the node with value 2.
Given 1->2, return the node with value 1.

Link

Lintcode_ladder

Method

1. x
2. x

Example

1. 1

   /**
   * Definition of ListNode
   * class ListNode {
   * public:
   *     int val;
   *     ListNode *next;
   *     ListNode(int val) {
   *         this->val = val;
   *         this->next = NULL;
   *     }
   * }
   */
   class Solution{
   public:
    /**
     * @param head: the head of linked list.
     * @return: a middle node of the linked list
     */
    ListNode *middleNode(ListNode *head) {
        // Write your code here
        if (!head) {
            return nullptr;
        }
        ListNode* slow = head;
        ListNode* fast = head->next;
        while (fast && fast->next) {
            slow = slow->next;
            fast = fast->next->next;
        }
        return slow;
    }
   };
   

Similar problems

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Tags

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