鏈表逆置

public class 單鏈表逆置 {

	public static void main(String[] args) {
		// 創建一個鏈表
		LinkedList head = new LinkedList();
		LinkedList head1 = new LinkedList();
		head1.s = "1";
		head1.next = null;

		LinkedList head2 = new LinkedList();
		head2.s = "2";
		head2.next = head1;

		LinkedList head3 = new LinkedList();
		head3.s = "3";
		head3.next = head2;
		head = head3;
		// 逆置前的
		printLinkedList(head);
		head = reverList(head);
		printLinkedList(head);
	}

	public static LinkedList reverList(LinkedList head) {
		LinkedList q = head;
		LinkedList p = q.next;
		LinkedList pr = null;
		q.next = null;// 先讓鏈表頭結點，也就是尾結點，置空。
		while (p != null) {
			pr = p.next;// 先保存下一個結點的位置
			p.next = q;// 修改當前結點的next的值
			q = p;// 向前移動
			p = pr;
		}

		return q;
	}

	public static void printLinkedList(LinkedList head) {
		LinkedList p = head;
		while (p != null) {
			System.out.println(p.s);
			p = p.next;

		}
	}

}

class LinkedList {
	String s;
	LinkedList next;

	public LinkedList() {
		// TODO Auto-generated constructor stub
	}

	LinkedList(String s, LinkedList next) {
		this.s = s;
		this.next = next;
	}
}