LC.P725[分隔链表]

方法一：模拟

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/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode[] splitListToParts(ListNode head, int k) {
        ListNode p = head;
        int n = 0;
        while (p != null) {
            p = p.next;
            ++n;
        }
        ListNode[] ans = new ListNode[k];
        int groupSize = n / k, reminder = n % k;
        ListNode cur = head;
        for (int i = 0; i < k && cur != null; ++i) {
            ans[i] = cur;
            int partSize = groupSize + (i < reminder ? 1 : 0);
            for (int j = 1; j < partSize; ++j) {
                cur = cur.next;
            }
            ListNode next = cur.next;
            cur.next = null;
            cur = next;
        }
        return ans;
    }
}
  • 时间复杂度：$O(n)$
  • 空间复杂度：$O(1)$