[数据结构与算法]合并多个链表

package main.java.demo23;

import main.java.ListNode;

/**
 *
 给你一个链表数组，每个链表都已经按升序排列。

 请你将所有链表合并到一个升序链表中，返回合并后的链表。


 */
public class MergeKLists {

    ListNode head = new ListNode();
    ListNode current = head;

    /**
     * 算法思路: 根据多次循环找到所有链表当前最小值, 再操作
     * @param lists
     * @return
     */
    public ListNode mergeKLists_1(ListNode[] lists) {
        int n = lists.length;
        Integer result = null;
        int resultIndex = 0;

        while (true) {
            for (int i = 0; i < n; i++) {
                if (lists[i] != null) {
                    if (result == null) {
                        result = lists[i].val;
                        resultIndex = i;
                    } else if (lists[i].val < result) {
                        result = lists[i].val;
                        resultIndex = i;
                    }
                }
            }
            if (result == null) {
                return head.next;
            }
            result = null;
            current.next = lists[resultIndex];
            current = current.next;
            lists[resultIndex] = lists[resultIndex].next;
        }
    }

}