LintCode1661. 删除链表中的第n到m个节点

描述

给定一个链表，删除链表中的第 n 到 m 个节点，返回链表的头节点。

编号从 00 开始

链表的长度不超过 100000100000

样例
样例 1：

输入：head = 1->2->3->4->5->null, n = 1, m = 2
输出：1->4->5->null
样例 2：

输入：head = 1->2->3->4->5->null, n = 1, m = 4
输出：1->null

/**
 * Definition for ListNode
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */

public class Solution {
    /**
     * @param head: The first node of linked list
     * @param n: the start index
     * @param m: the end node
     * @return: A ListNode
     */
    public ListNode deleteNode(ListNode head, int n, int m) {
        // Write your code here
            ListNode nodeNc = head;
        if (n == 0) {
            int count = 0;
            while (head != null && count <= m) {
                head = head.next;
                count++;
            }
            return head;
        } else {
            int count1 = 0;
            while(head!=null && count1 < n-1){
                head = head.next;
                count1++;
            }
            int count2 = 0;
            ListNode nodem = nodeNc;
            while (head!= null && count2 <= m ){
                nodem = nodem.next;
                count2++;
            }
            head.next = nodem;
            return nodeNc;
  	  }
    }
}