题解 | #合并两个排序的链表#

package main
import . "nc_tools"

/*
 * type ListNode struct{
 *   Val int
 *   Next *ListNode
 * }
 */

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param pHead1 ListNode类
 * @param pHead2 ListNode类
 * @return ListNode类
 */
//双指针方；把列表L2->合并到L1当中; L1多一个dummy Head, 保证是L2往L1迁移；
//L1,L2的头分别指向最小的
//L1.Val < L2.Val && L1.Next.Val -> <= L2.Val {-> 移动 L1; -> 插入L2的val值; L2移动}； 直到有一方为空
func Merge(pHead1 *ListNode, pHead2 *ListNode) *ListNode {
	// write code here
	if pHead1 == nil {
		return pHead2
	}
	if pHead2 == nil {
		return pHead1
	}
	dummy := &ListNode{Val: -10000, Next: pHead1}
	h1 := dummy
	h2 := pHead2
	for h1.Next != nil && h2 != nil {
		temp := h1.Next
		if temp.Val <= h2.Val {
			h1 = temp
			continue
		}
		temp2 := h2.Next
		h2.Next = temp
		h1.Next = h2
		h2 = temp2
	}
	if h1.Next == nil {
		h1.Next = h2
	}
	return dummy.Next

}