面试题25：合并两个排序的链表

NowCoder

<?php
header("content-type:text/html;charset=utf-8");
/** 输入两个单调递增的链表，输出两个链表合成后的链表，当然我们需要合成后的链表满足单调不减规则。 P145*/
class ListNode{var $val;var $next = NULL;function __construct($x){$this->val = $x;}
}
function Merge($pHead1, $pHead2)
{if($pHead1 == null){return $pHead2;}if($pHead2 == null){return $pHead1;}//  $pHead = new ListNode(null);if($pHead1->val <= $pHead2->val){$pHead = $pHead1;$pHead->next = Merge($pHead1->next,$pHead2);}else{$pHead = $pHead2;$pHead->next = Merge($pHead1,$pHead2->next);}return $pHead;
}$head1 = new ListNode(1);
$head1->next = new ListNode(4);
$head1->next->next = new ListNode(5);
$head1->next->next->next = new ListNode(7);
$head1->next->next->next->next = new ListNode(8);
$head1->next->next->next->next->next = new ListNode(12);$head2 = new ListNode(1);
$head2->next = new ListNode(3);
$head2->next->next = new ListNode(6);
$head2->next->next->next = new ListNode(9);
$head2->next->next->next->next = new ListNode(11);print_r(Merge($head1,$head2));