剑指 Offer 25. 合并两个排序的链表

class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode merge = new ListNode(0);
        ListNode temp = merge;

        while(l1 != null && l2 != null){
            if(l1.val < l2.val){

                temp.next = l1;
                l1 = l1.next;
            } else {
                temp.next = l2;
                l2 = l2.next;
            }

            temp = temp.next;
        }

        temp.next = l1 == null ? l2 : l1;

        return merge.next;
    }
}

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    def mergeTwoLists(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        merge = ListNode(0)
        temp = merge

        while l1 and l2:
            if l1.val < l2.val:
                temp.next = l1
                l1 = l1.next
            else:
                temp.next = l2
                l2 = l2.next

            temp = temp.next

        temp.next = l1 if l1 else l2

        return merge.next

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
        ListNode* merge = new ListNode(0);
        ListNode* temp = merge;

        while (l1 && l2) {
            if (l1->val < l2->val) {
                temp->next = l1;
                l1 = l1->next;
            } else {
                temp->next = l2;
                l2 = l2->next;
            }

            temp = temp->next;
        }

        temp->next = l1 ? l1 : l2;

        return merge->next;
    }
};

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func mergeTwoLists(l1 *ListNode, l2 *ListNode) *ListNode {
    merge := &ListNode{}
    temp := merge

    for l1 != nil && l2 != nil {
        if l1.Val < l2.Val {
            temp.Next = l1
            l1 = l1.Next
        } else {
            temp.Next = l2
            l2 = l2.Next
        }

        temp = temp.Next
    }

    if l1 != nil {
        temp.Next = l1
    } else {
        temp.Next = l2
    }

    return merge.Next
}

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */
var mergeTwoLists = function(l1, l2) {
    let merge = new ListNode(0);
    let temp = merge;

    while (l1 != null && l2 != null) {
        if (l1.val < l2.val) {
            temp.next = l1;
            l1 = l1.next;
        } else {
            temp.next = l2;
            l2 = l2.next;
        }

        temp = temp.next;
    }

    temp.next = l1 == null ? l2 : l1;

    return merge.next;
};