[LeetCode] Merge Two Sorted Lists
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.
/** * 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 *head = NULL,*p=NULL,*temp; if(l1 != NULL || l2 !=NULL){ if(l1 != NULL && l2 !=NULL){ if(l1->val < l2->val){ head = l1; l1= l1->next; } else{ head = l2; l2 = l2->next; } } else if(l1 != NULL){ head = l1; l1= l1->next; } else{ head = l2; l2 = l2->next; } }//end if p = head; while(l1 != NULL && l2 != NULL){ if(l1->val<l2->val){ temp = l1; l1 = l1->next; } else{ temp = l2; l2 = l2->next; } p->next = temp; p = p->next; }//end while while(l1 != NULL){ p->next = l1; l1 = l1->next; p = p->next; }//end while while(l2 != NULL){ p->next = l2; l2 = l2->next; p = p->next; }//end while if(p) p->next = NULL; return head; } };