lintcode:Merge Two Sorted Lists

Merge two sorted (ascending) linked lists and return it as a new

sorted list. The new sorted list should be made by splicing together

the nodes of the two lists and sorted in ascending order.

Given 1->3->8->11->15->null, 2->null ,

return 1->2->3->8->11->15->null.

题目很简单。

注意一点，最后如果p1或者p2非空时，只需要把p1或p2链接到newp->next即可，而不需要逐个的元素添加。

/**
* Definition of ListNode
* class ListNode {
* public:
*     int val;
*     ListNode *next;
*     ListNode(int val) {
*         this->val = val;
*         this->next = NULL;
*     }
* }
*/
class Solution {
public:
/**
* @param ListNode l1 is the head of the linked list
* @param ListNode l2 is the head of the linked list
* @return: ListNode head of linked list
*/
ListNode *mergeTwoLists(ListNode *l1, ListNode *l2) {
// write your code here
ListNode *newl=new ListNode(0);
ListNode *newp=newl;

ListNode *p1=l1,*p2=l2;
while(p1 && p2){

if(p1->val<p2->val){
newp->next=p1;
newp=newp->next;
p1=p1->next;
}else{
newp->next=p2;
newp=newp->next;
p2=p2->next;
}

}

if(p1){
newp->next=p1;
}else{
newp->next=p2;
}

return newl->next;
}
};