leetcode Merge k Sorted Lists(Java)

题目链接：点击打开链接

类型：合并

解法：分治

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { val = x; } * } */public class Solution {    public ListNode mergeKLists(ListNode[] lists) {int len = lists.length;return partition(lists, 0, len-1);    }        private ListNode partition(ListNode[] lists, int s, int e){if (s == e) return lists[s];if (s < e){int m = (s+e)/2;ListNode r1 = partition(lists, s, m);ListNode r2 = partition(lists, m+1, e);return merge(r1, r2);}else{return null;}}private ListNode merge(ListNode l1, ListNode l2){if (l1 == null) return l2;if (l2 == null) return l1;if (l1.val < l2.val){l1.next = merge(l1.next, l2);return l1;}else{l2.next = merge(l1, l2.next);return l2;}}        }