Solution.java

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode[] splitListToParts(ListNode root, int k) {
        int n = 0;
        ListNode cur = root;
        while (cur != null) {
            ++n;
            cur = cur.next;
        }
        // width 表示每一部分至少含有的结点个数
        // remainder 表示前 remainder 部分，每一部分多出一个数
        int width = n / k, remainder = n % k;
        ListNode[] res = new ListNode[k];
        cur = root;
        for (int i = 0; i < k; ++i) {
            ListNode head = cur;
            for (int j = 0; j < width + ((i < remainder) ? 1 : 0) - 1; ++j) {
                if (cur != null) {
                    cur = cur.next;
                }
            }
            if (cur != null) {
                ListNode t = cur.next;
                cur.next = null;
                cur = t;
            }
            res[i] = head;
        }
        return res;
    }
}