Leetcode 2. Add Two Numbers | Add digits of two linked lists and return their sum | Linked List

Check out our other playlists:

Dynamic Programming:

Trees:

Heaps and Maps:

Arrays and Maths:

Bit Manipulation:

Greedy Algorithms:

Sorting and Searching:

Strings:

Linked Lists:

Stack and Queues:

Two Pointers:

Graphs, BFS, DFS:

Backtracking:

Non- DSA playlists:

Probability:

SQL-Basic Join functions:

SQL-Basic Aggregate functions:

You can avoid some code duplication by doing like this:

public ListNode addTwoNumbers(ListNode l1, ListNode l2) {

ListNode l3 = new ListNode(-1);
ListNode l3Head = l3;
int carry = 0;

while (l1 != null || l2 != null){

int l1Val = 0;
if (l1 != null) {
l1Val = l1.val;
l1 = l1.next;
}

int l2Val = 0;
if (l2 != null){
l2Val = l2.val;
l2 = l2.next;
}

int value = l1Val + l2Val + carry;
l3.next = new ListNode(value % 10);
carry = value / 10;

l3 = l3.next;

}

if (carry != 0){
l3.next = new ListNode(carry);
}

return l3Head.next;

}

[lifekool]

in depth knowledge of how to solve a particular problem and how to take care of edge cases. Best explanation ever <3

[ParthG-viml]

really 😃 breaking down the problem into smaller chunks & solving every chunk 1 by 1 is the best thing of this channel.

[RashidIqbal-ii]

I see many videos, but you explain very well. Best explanation and easy to understand.

[DG_Theniel]

been looking several videos of this problem. This is by far the best explaination video I have ever seen. Finally someone who can shove down information in my brain. Thank you

[SleepyBaseball-tsse]

Ma'am, I'm working with java but I got complete logic of the code Hats off to you Ma'am

[viencong]

100 point for you. Love you very much for explain so eassy to understand

[alastairhewitt]

One of the best explanations I've seen. However, what is still throwing me off with LeetCode's solution was that they had l3 = head rather than head = l3 as you have here and I have been hung up on it for a while. I would appreciate it a lot if you could please help me understand why the order of the assignment doesn't seem to matter 🙏🙏🙏

[MdineshKumar-gpwg]

i started coding last few weeks.your viedoes was so helpful to me .thank you

[rakeshruler]

You explained it in student way thank you for the simple logic ! A lots of love

[namrathas]

Thank you so much Alisha, your code and explanation was so easy to understand.

[abhi_jit_tripathy]

thank you so much for this great explanation....I soled this problem in 3 different ways but some test cases didn't ran...When i saw ur explanation it was super easy...thanks a lot for

[hemantdixit]

so much clarity in your explanation, amazing

[sreeharsha]

but it is always recommended to do in constant space right ?

[probabilitycodingisfunis]

ListNode* l3 = new ListNode(0);
int carry =0;
ListNode* head = l3;
while(l1 && l2)
{
int value = l1->val+l2->val+carry;
carry = value/10;
l3->next = new ListNode(value%10);
l3 = l3->next;
l1 = l1->next;
l2 = l2->next;
}

while(l1)
{
int value = l1->val+carry;
carry = value/10;
l3->next = new ListNode(value%10);
l3 = l3->next;
l1 = l1->next;

}

while(l2)
{
int value = l2->val+carry;
carry = value/10;
l3->next = new ListNode(value%10);
l3 = l3->next;
l2 = l2->next;

}

if(carry)
{
l3 ->next = new ListNode(carry);
}
return head->next;

[PRITYKUMARI-znro]

your explanation is so smooth and clear.thanks.
can you plz mention time complexity with your solution..it would be very useful.

[mayankjaiswal]

Whats d point of doing that if we r taking new list
It is advisable to do in same list without taking any extra space

[syedmunawar]

I am begining to code and your video is helpful

[negi-ji]

thankew thankew thankew ! itna ache se samjhane ke liye. i was stuck in this problem because of the corner cases. Baaki videos se kuch khaas samaj nahi aya but with this video i got it all in one go! replay bhi nahi karna pada and i wrote it in java. once again thanking you🫂... bhagwan aapko ek world tour gift kar de meri taraf se🙏

[darshanpancholi]

just loved the way you explained....❤❤