题解 | #合并k个已排序的链表#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */
/**
 * 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 lists ListNode类一维数组 
 * @param listsLen int lists数组长度
 * @return ListNode类
 */
struct ListNode* merge(struct ListNode *pHead1, struct ListNode *pHead2)
{
    struct ListNode *p = malloc(sizeof(struct ListNode));
    struct ListNode *ans = p;
    while(pHead1 && pHead2)
    {
        if(pHead1->val <= pHead2->val)
        {
            p->next = pHead1;
            pHead1 = pHead1->next;
        }
        else 
        {
            p->next = pHead2;
            pHead2 = pHead2->next;
        }
        p = p->next;
    }
    pHead1? (p->next=pHead1) : (p->next=pHead2);
    return ans->next;
}

struct ListNode* mergeKLists(struct ListNode** lists, int listsLen ) {
    // write code here
    if(!listsLen)
    {
        return NULL;
    }
    struct ListNode *p = NULL; 
    for(int i=0;i<listsLen;i++)
    {
        p = merge(p, lists[i]);
    }
    return p;
}