Find intersection of two linked lists

Given two linked lists.Find intersection of the two linked lists.

[WowPlusWow]

Damn, I can't believe I haven't thought of this method. Great video.

[cseinterviewprep]

Nice Explanation. Here is the another way without determining the length of the linked list.
1. Start iterating both the lists from the head node (pointer: list1 for first list and list2 for second list).
2.Interchange the pointers if any of the list is terminated

For eg:
list1: 1->2>3->10->11
list2: 5->10->11
ptr1=list1
ptr2 = list2
after three iterations,
ptr2 will point to head of list1 : 1->2->3->10->11 while the ptr1 pointer is still point to 10 of the list1
after 3 more iterations,
ptr1 is pointing to 10(list2) and ptr2 is pointing to 10 (list1)

[vaibhavkumar]

This method will not pass a few test cases like:
when you have two similar nodes before the intersection point listA = [4, 1, 8, 4, 5], listB = [5, 6, 1, 8, 4, 5], Above code will get you 1 while it should be 8

[abhishekvishwakarma]

Thank you so much sir for teaching in such a simple way 🙏

[biswadeepchakraborty]

Hi bro your explanations are very clear and helpful. Thanks

[rrsonia]

thanks for the video. Correct me if Im wrong, this approach will not work in this situation :
listA = [4, 1, 8, 4, 5]
listB = [5, 0, 1, 8, 4, 5]
intersectVal = 8
because before it gets to the intersection point, node values are already the same (i.e 1) and it will jump out of the loop.

[maged_helmy]

Python code without having to compare lengths. You basically jump to the other list when you come to the end of the list. This way, if there is a connection it is guaranteed to meet at the link.
````
class Solution:
def getIntersectionNode(self, headA: ListNode, headB: ListNode) -> ListNode:
if not headA or not headB:
return None

savedA, savedB = headA, headB

while headA != headB:
headA = savedB if not headA else headA.next
headB= savedA if not headB else headB.next

return headA
```

[Techjai]

good logic actually i tried of doing with comparing pointer of 1st linked list with that of second resulting in increase of time complexity and this approach was cool

[HarshaVardhan-jfsd]

u cud use a hashmap to store the address and compare it when traversing both the linked lists

[northstaar]

What if two linked list have same node but it's not intersection? It's possible to have same node and before intersection itself..

[karthikrashinkar]

what is it was 'd' in 2nd linked list in place of n??

[biswadeepchakraborty]

Could you make tutorials on hard sections of HackerRank Problem Solving including both Data Structure and algorithms. Your tutorials are great and thanks for your effort

[rflxplays]

sir could you please make a video on XOR linked list, SKIP list, UNROLLED list..

[dantewhite]

please put the link to the video on how to calculate the length of the list in the description thanks for the awesome vide and please write out some code to help us out thanks
you are so awesome and I love you

[dharnachandrakar]

this is merging point of two link list.., intersection is different

[CodeWithGotu]

Please take github in description or code link

[debaratighatak]

what a nice algorithm, thank you sir!

[shanpalaniram]

Lets assume that the length of list is bigger. What is the easy way to find in that case?

[youloose]

How do we find the intersection of two lists of equal lengths in C

[murugesh]

what if "e" present ar "a" the location of first linkedlist and "m" the location of second linkedlist