package chapter_2_listproblem;
public class Problem_19_MergeTwoLinkedLists {
public static class Node {
public int value;
public Node next;
public Node(int data) {
this.value = data;
}
}
public static Node merge(Node head1, Node head2) {
if (head1 == null || head2 == null) {
return head1 != null ? head1 : head2;
}
Node head = head1.value < head2.value ? head1 : head2;
Node cur1 = head == head1 ? head1 : head2;
Node cur2 = head == head1 ? head2 : head1;
Node pre = null;
Node next = null;
while (cur1 != null && cur2 != null) {
if (cur1.value <= cur2.value) {
pre = cur1;
cur1 = cur1.next;
} else {
next = cur2.next;
pre.next = cur2;
cur2.next = cur1;
pre = cur2;
cur2 = next;
}
}
pre.next = cur1 == null ? cur2 : cur1;
return head;
}
public static void printLinkedList(Node head) {
System.out.print("Linked List: ");
while (head != null) {
System.out.print(head.value + " ");
head = head.next;
}
System.out.println();
}
public static void main(String[] args) {
Node head1 = null;
Node head2 = null;
Node head = merge(head1, head2);
printLinkedList(head);
head1 = new Node(1);
head2 = null;
head = merge(head1, head2);
printLinkedList(head);
head1 = null;
head2 = new Node(1);
head = merge(head1, head2);
printLinkedList(head);
head1 = new Node(1);
head2 = new Node(2);
head = merge(head1, head2);
printLinkedList(head);
head1 = new Node(2);
head2 = new Node(1);
head = merge(head1, head2);
printLinkedList(head);
head1 = new Node(1);
head1.next = new Node(4);
head2 = new Node(2);
head2.next = new Node(3);
head2.next.next = new Node(5);
head = merge(head1, head2);
printLinkedList(head);
head1 = new Node(1);
head1.next = new Node(3);
head1.next.next = new Node(5);
head1.next.next.next = new Node(7);
head1.next.next.next.next = new Node(9);
head2 = new Node(0);
head2.next = new Node(6);
head2.next.next = new Node(6);
head2.next.next.next = new Node(7);
head = merge(head1, head2);
printLinkedList(head);
}
}