两个链表的第一个公共结点

来源：互联网发布：配置php开发环境编辑：程序博客网时间：2024/06/06 16:33

题目：输入两个链表，找出它们的第一个公共结点。

package offer;/* * 两个链表的第一个公共结点 */public class FindFirstCommonNode {public static ListNode findFirstCommonNode(ListNode root1, ListNode root2){int length1 = getListLength(root1);int length2 = getListLength(root2);int lengthDif = length1 - length2;ListNode headLong = root1;ListNode headShort = root2;if(length2>length1){headLong = root2;headShort = root1;lengthDif = length2 - length1;}//先在长链表上走几步for(int i=0; i<lengthDif; i++)headLong = headLong.next;while(headLong!=null && headShort!=null && headLong != headShort){headLong = headLong.next;headShort = headShort.next;}//得到第一个公共结点ListNode commonNode = headLong;return commonNode;}private static int getListLength(ListNode root){int length=0;ListNode head = root;while(head!=null){length++;head = head.next;}return length;}}

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