021.merge-two-sorted-lists.go

// https://leetcode.com/problems/merge-two-sorted-lists/

package leetcode

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func mergeTwoLists(l1 *ListNode, l2 *ListNode) *ListNode {
	var h ListNode
	l := &h
	for l1 != nil && l2 != nil {
		if l1.Val < l2.Val {
			l.Next, l1 = l1, l1.Next
		} else {
			l.Next, l2 = l2, l2.Next
		}
		l = l.Next
	}
	if l1 != nil {
		l.Next = l1
	} else if l2 != nil {
		l.Next = l2
	}
	return h.Next
}