Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists
1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next; 6 * ListNode(int x) : val(x), next(NULL) {} 7 * }; 8 */ 9 class Solution { 10 public: 11 ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) { 12 ListNode* newHead = new ListNode(-1); 13 ListNode* tail = newHead; 14 15 while(l1 != NULL && l2 != NULL) 16 { 17 if(l1->val <= l2->val){ 18 tail->next = l1; 19 l1 = l1->next; 20 } 21 else{ 22 tail->next = l2; 23 l2 = l2->next; 24 } 25 tail =tail->next; 26 } 27 if(l1 != NULL){ 28 tail->next = l1; 29 }else if(l2 != NULL){ 30 tail->next = l2; 31 } 32 return newHead->next; 33 } 34 };