[Question]
Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.
Question]
Merge K ordered linked lists
[Idea] merge
[Code]
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {public: ListNode* merge(vector
&lists, int start, int end){ if(start==end)return lists[start]; int mid=(start+end)/2; ListNode*p1=merge(lists, start, mid); ListNode*p2=merge(lists, mid+1, end); ListNode*head=NULL, *p=NULL; while(p1&&p2){ if(p1->val
val){ if(p)p->next=p1; p=p1; p1=p1->next; } else{ if(p)p->next=p2; p=p2; p2=p2->next; } if(head==NULL)head=p; } if(p1){ if(p)p->next=p1; else{p=p1;head=p;} } if(p2){ if(p)p->next=p2; else{p=p2;head=p;} } return head; } ListNode *mergeKLists(vector
&lists) {int size=lists.size();if(size==0) return NULL;if(size==1) return lists[0];return merge(lists, 0, size-1); }};