题解 | #合并两个排序的链表#

一、比较大小一个一个结点插入

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pHead1 ListNode类 
     * @param pHead2 ListNode类 
     * @return ListNode类
     */
    ListNode* Merge(ListNode* pHead1, ListNode* pHead2) {
        // write code here
        ListNode* nHead = new ListNode(0);
        ListNode* node = nHead;
        while(pHead1!=NULL&&pHead2!=NULL)
        {
            if(pHead1->val<=pHead2->val)
            {
                node->next = pHead1;
                pHead1 = pHead1->next;
            }
            else
            {
                node->next = pHead2;
                pHead2 = pHead2->next;
            }
            node = node->next;
        }
	  //这个地方一脑抽写成pHead1了...
        if(pHead1==NULL)node->next = pHead2;
        else node->next = pHead1;
        return nHead->next;
    }
};