package problems.geeks.linkedlist;
/**
* Get Nth node in a Linked List
*
* Write a GetNth() function that takes a linked list and an integer index and returns the data value stored in the node at that index position.
*
* Algorithm:
*
* 1. Initialize count = 0
* 2. Loop through the link list
* a. if count is equal to the passed index then return current
* node
* b. Increment count
* c. change current to point to next of the current.
*
* 切记，从头往前找第 n 个节点的时候，利用一个计数器来帮助查找，代码会显得比较干净
*/
import java.util.*;
import adt.ListNode;
import adt.LinkedList;
public class Q001_Get_Nth_Node {
static ListNode getNth(ListNode head, int n) {
if (head == null) {
return null;
}
int count = 1;
ListNode p = head;
while (p != null && count < n) {
p = p.next;
count++;
}
// p 要么是 null，要么就是我们要找的第 n 个
return p;
}
public static void main(String[] args) {
// Initialize a linked list
LinkedList list = new LinkedList(10);
ListNode node = getNth(list.head, 5);
if (node != null) {
System.out.println(node.val);
} else {
System.out.println("No such node");
}
}
}