Leetcode 160. Intersection of Two Linked Lists || intuition with code

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.



Example 1:

Input: intersectVal = 8, listA = [4,1,8,4,5], listB = [5,6,1,8,4,5], skipA = 2, skipB = 3
Output: Reference of the node with value = 8
Input Explanation: The intersected node's value is 8 (note that this must not be 0 if the two lists intersect). From the head of A, it reads as [4,1,8,4,5]. From the head of B, it reads as [5,6,1,8,4,5]. There are 2 nodes before the intersected node in A; There are 3 nodes before the intersected node in B.


Example 2:

Input: intersectVal = 2, listA = [1,9,1,2,4], listB = [3,2,4], skipA = 3, skipB = 1
Output: Reference of the node with value = 2
Input Explanation: The intersected node's value is 2 (note that this must not be 0 if the two lists intersect). From the head of A, it reads as [1,9,1,2,4]. From the head of B, it reads as [3,2,4]. There are 3 nodes before the intersected node in A; There are 1 node before the intersected node in B.

[khyzylmikhail]

thanks for the explanation. it did clear all concepts 🙏

[RiteshYadav-mv]

Thanks for the explanation ..hats off to you😊 !!

[gowrisankarjammu]

awesome and great explantion by alish mam

[aayushranjan]

1st app code

ListNode *temp;
while(headA != NULL){
temp = headB;
while(temp != NULL){
if(headA == temp){
headA;
}
temp = temp -> next;
}
headA = headA -> next;
}
return NULL;

[AyushPatel-kb]

What is thr time&space complexity of last approach?

[Harshal-dkkr]

once they meet, then they should marry with each other😂

[prakhar]

Hey thats great logic.. can u please tell the time complexity for this sol where we are interchanging the heads?

[shashankkshetty]

great work sis, learnt a lot from your videos. I used set initially and got the answer but wanted to optimize it, so i tried slow and fast pointer approach which didnt work, then came here to get the best solution.

[ASIFAlI-lqrd]

One request please give your code here....

[MotivationWithNitish]

But ma'am why 1 is not starting intersection of both Linked Lists

[chaitanyanimma]

This approach is working and we can see with example also whether it is working or not, but is there a way to know why this works? when I saw this approach some days back, I wondered why is it working!! I am asking so that I can be sure how it works! If you can explain, it'll be helpful