题解 | #合并两个排序的链表#

递归实现

明白递归函数的功能和递归出口

struct ListNode {
	int val;
	struct ListNode *next;
	ListNode(int x) :
			val(x), next(NULL) {
	}
};*/
class Solution {
public:
    ListNode* Merge(ListNode* pHead1, ListNode* pHead2) {
        if(!pHead1) return pHead2;
        if(!pHead2) return pHead1;
        if(pHead1->val <= pHead2->val){
            pHead1->next = Merge(pHead1->next, pHead2);
            return pHead1;
        }
        else{
            pHead2->next = Merge(pHead1, pHead2->next);
            return pHead2;
        }
    }
};