Linked List Orta Nokta

https://leetcode.com/explore/challenge/card/30-day-leetcoding-challenge/529/week-2/3290/

>> Solution 1 : Find Size, Then Middle

O(n) time, O(1) space


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	/**
	* Definition for singly-linked list.
	* public class ListNode {
	* int val;
	* ListNode next;
	* ListNode(int x) { val = x; }
	* }
	*/
	class LinkedListMiddleNode {
	public ListNode solve(ListNode head) {
	int size = 0;
	// Go to the last node to find the size
	ListNode current = head;
	while(current != null) {
	current = current.next;
	size++;
	}
	int middle = size/2;
	// Go to the middle node
	current = head;
	for(int i=0; i < middle; i++) {
	current = current.next;
	}
	return current;
	}
	}

view raw LinkedListMiddleNode.java hosted with ❤ by GitHub

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>> Solution 2 : Slow and Fast Pointer

O(n) time, O(1) space

--

	/**
	* Definition for singly-linked list.
	* public class ListNode {
	* int val;
	* ListNode next;
	* ListNode(int x) { val = x; }
	* }
	*/
	class LinkedListMiddleNodeFastPointer {
	public ListNode middleNode(ListNode head) {
	ListNode sizePointer = head;
	ListNode middlePointer = head;
	while(sizePointer != null && sizePointer.next != null) {
	middlePointer = middlePointer.next;
	sizePointer = sizePointer.next.next;
	}
	return middlePointer;
	}
	}

view raw LinkedListMiddleNodeFastPointer.java hosted with ❤ by GitHub

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