package ZHIHU;

public class Main20171009001 {

	/**
	 * 輸入兩個遞增排序的連結串列，合併這兩個連結串列並使新連結串列中的結點仍然是按照遞增排序的
	 */
	public static void main(String[] args) {

		ListNode head1 = new ListNode();
		head1.value = 1;
		head1.next = new ListNode();
		head1.next.value = 2;
		head1.next.next = new ListNode();
		head1.next.next.value = 3;
		head1.next.next.next = new ListNode();
		head1.next.next.next.value = 4;
		head1.next.next.next.next = new ListNode();
		head1.next.next.next.next.value = 5;
		ListNode head2 = new ListNode();
		head2.value = 1;
		head2.next = new ListNode();
		head2.next.value = 3;
		head2.next.next = new ListNode();
		head2.next.next.value = 5;
		head2.next.next.next = new ListNode();
		head2.next.next.next.value = 6;
		head2.next.next.next.next = new ListNode();
		head2.next.next.next.next.value = 7;

		ListNode root = merge2(head1, head2);
		System.out.println("--------------------------");
		printList(root);
		System.out.println("--------------------------");
		printList(head1);
	}

	private static class ListNode {
		int value;
		ListNode next;
	}

	// 破壞原來的兩個連結串列的結構
	public static ListNode merge(ListNode head1, ListNode head2) {

		if (head1 == null) {
			return head2;
		}
		if (head2 == null) {
			return head1;
		}
		ListNode root = new ListNode();
		ListNode p = root;
		while (head1 != null && head2 != null) {
			if (head1.value <head2.value) {
				p.next = head1;
				head1 = head1.next;
			} else {
				p.next = head2;
				head2 = head2.next;
			}
			p = p.next;
		}
		if (head1 != null) {
			p.next = head1;
		}
		if (head2 != null) {
			p.next = head2;
		}
		return root.next;
	}

	// 不破壞原來的兩個連結串列的結構
	public static ListNode merge2(ListNode head1, ListNode head2) {
		if (head1 == null) {
			return head2;
		}
		if (head2 == null) {
			return head1;
		}
		ListNode root = new ListNode();
		ListNode p = root;

		while (head1 != null && head2 != null) {
			if (head1.value <head2.value) {
				ListNode node = new ListNode();
				node.value = head1.value;
				node.next = null;
				p.next = node;
				head1 = head1.next;
			} else {
				ListNode node = new ListNode();
				node.value = head2.value;
				node.next = null;
				p.next = node;
				head2 = head2.next;
			}
			p = p.next;
		}
		while (head1 != null) {
			ListNode node = new ListNode();
			node.value = head1.value;
			node.next = null;
			p.next = node;
			p = p.next;
			head1 = head1.next;
		}
		while (head2 != null) {
			ListNode node = new ListNode();
			node.value = head2.value;
			node.next = null;
			p.next = node;
			p = p.next;
			head2 = head2.next;
		}
		return root.next;
	}


	private static void printList(ListNode head) {
		ListNode p = head;
		while (p != null) {
			System.out.print(p.value + " ");
			p = p.next;
		}
		System.out.println();
	}
}