Intersection of Two Linked List

Problem

Write a program to find the node at which the intersection of two singly linked lists begins.

For example, the following two linked lists: begin to intersect at node c1.
Notes:

• If the two linked lists have no intersection at all, return null.
• The linked lists must retain their original structure after the function returns.
• You may assume there are no cycles anywhere in the entire linked structure.
• Your code should preferably run in O(n) time and use only O(1) memory.

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Idea

统计两个链表的长度
以短的为基准对齐两个链表的start node
从新的起点开始，两个链表遍历，找第一个相同的元素

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Solution

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