Leetcode43: 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.

用归并排序的思想。

/** * 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* merge = new ListNode(0);        ListNode* head = merge;        while(l1&&l2)        {            if(l1->val < l2->val)            {                merge->next = l1;                l1 = l1->next;                merge = merge->next;            }            else            {                merge->next = l2;                l2 = l2->next;                merge = merge->next;            }        }                if(l1)        {            merge->next = l1;        }        if(l2)        {            merge->next = l2;        }                return head->next;    }};