链表类常见算法题总结

链表类常见算法题目总结

1.反转链表

翻转思想：



代码实现：

public class SinglyLinkedList_reverse {

public static <T> void reverse(MSinglyLinkedList<T> list) {
Node<T> p = list.head.next, succ = null, front = null;
while (p != null) {
succ = p.next;//保存p的后继节点
p.next = front;//使得p.next指向其前驱front
front = p;
p = succ;
}
list.head.next = front;
}

public static void main(String[] args) {
String[] values = { "A", "B", "C", "D", "E", "F" };
MSinglyLinkedList<String> list = new MSinglyLinkedList<String>(values);
System.out.println("翻转前" + list.toString());
reverse(list);
System.out.println("翻转后" + list.toString());

}
}

2.给定一个链表，删除链表中倒数第n个节点，返回链表的头节点。

样例

给出链表1->2->3->4->5->null和 n = 2.

删除倒数第二个节点之后，这个链表将变成1->2->3->5->null.

/**
* @param head: The first node of linked list.
* @param n: An integer.
* @return: The head of linked list.
*/
ListNode removeNthFromEnd(ListNode head, int n) {
if (n <= 0) {
return null;
}

ListNode dummy = new ListNode(0);
dummy.next = head;

ListNode preDelete = dummy;
for (int i = 0; i < n; i++) {
if (head == null) {
return null;
}
head = head.next;
}
while (head != null) {
head = head.next;
preDelete = preDelete.next;
}
preDelete.next = preDelete.next.next;
return dummy.next;
}