Intersection of Linked lists two linked list find coincident nodes

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

For example, the following, linked lists:

A:          a1→a2                                        c1→c2→c3                               B:     b1→b2→b3

Begin to intersect at node C1.

Notes:

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

Credits:
Special thanks to @stellari for adding this problem and creating all test cases.

Hide TagsLinked List

/** Definition for singly-linked list. * struct ListNode {* int val; * ListNode *next; * ListNode (int x) : Val (x), Next (NULL) {}}; */classSolution { Public: ListNode*getintersectionnode (ListNode *heada, ListNode *headb) {        intLena=0, lenb=0; ListNode*tempa=Heada; ListNode*tempb=headb;  while(Tempa) {LenA++; Tempa=tempa->Next; }         while(TEMPB) {LenB++; TEMPB=tempb->Next; }         while(lena>LenB) {Heada=heada->Next; LenA--; }         while(lenb>LenA) {headb=headb->Next; LenB--; }         while(Heada! =headb) {Heada=heada->Next; HEADB=headb->Next; }        returnHeada; }};

Intersection of Linked lists two linked list find coincident nodes