Find Middle of a singly linked list(Algorithm/Code/Program)

Given a linked list. Find the middle of the singly linked list.

[vikassanwal]

Awesomely simple! Best and clear-cut, to-the-point explanation, just the way it should be! Thanks a ton :)

[gurjotahuja]

You make it look so easy! Good work Mr Vivekanand! Keep it up

[ajayaman]

I learned a lot from ur channel...awesome explanation... big big thanks

[holyshit]

Splitting linked list in the two pieces If the condition for while loop is false at the begining then first piece is empty, second has at most head element (if list is empty both pieces are empty)
If while condition is fulfilled at least once we should break the list just before node you found
For splitting node we have to consider borded cases - at most one node on the list
If we have more than one node we need node previous to that you found
If the list has more then one element you are looking the begining of the second piece
but more useful would be end of the first piece
Your algorithm could be accepted for splitting linked list if it gives c node as a result in both your
examples then for border cases head as midpoint will be ok

[Lucho]

Thanks for the help men! Greatly appreciated!

[ViiCiiOUZ]

Amazing explanation, thank you good Sir

[neetusharma]

Sir can plz explain how to write module & procedure in data structure.
e. g. An array A contains 25 positive integers. Write a module to find all the pair of number whose sum is 25.

[AshishBurnwal]

Thank you so much for the nice explanation

[naginenikarthik]

For even number of elements, and get the output as 'c'. Can you give the code ..

[wasit-shafi]

nice sir... but u don't handle other cases like if linked is empty, if there is only 1/2 element in linked list...

[avssridhar]

will this work for more than 5 or 6 elements?

[ashishbasantani]

Sir what if we have only 2 elements in linked list in that case the output should be 1st element (2/2=1) but according to your approach o/p will be 2nd element.

[muskanrath]

please post alg/code for number of duplicates of a number in a linked list

[ajayaman]

please upload a tutorial of tower of Hanoi....without

[shivasureshreddysiva]

sir please upload singly, doubly, circular link list all topics

[ashishsinha]

plz brother make videos on selection, bubble sort by changing

[holyshit]

In doubly linked list we could traverse from both directions from head to tail using next pointers
and from tail to head using prev pointers
For singly linked list we can use two pointers, first goes once per iteration and second goes twice per iteration
For merge sort purpose c node should be tail node of first sublists in both examples

Lets consider modification to your algorithm

node * find_middle(node * head)
{
node *p, *q;
p = head;
q = head;
while(q != NULL && q->next !=NULL)
{
q = q->next->next;
if(q !=NULL)
p = p->next;
}
return p;
}
Now we can split linked list into halves which is necessary for merge sort

[rishabhsingh-gwnm]

merge two sorted linked list plz upload this video also

[holyshit]

If we want to use this function as subroutine for merge sort this function needs correction
I see two ways to correct this function

// Left sublist longer convention

node * find_middle(node *head)
{
node *p, *q;
p = head;
q = head;
while(q != NULL && q->next != NULL)
{
q = q->next->next;
if(q != NULL)
p = p->next;
// I changed order of instructions and added if statement
}
return p;
}

// Right sublist longer

node * find_middle(node *head)
{
node *p, *q, *r;
p = head;
q = head;
r = NULL;
// I introduced pointer to previous node of his middle node
while(q != NULL && q->next != NULL)
{
r = p;
p = p->next;
q = q->next->next
}
return r;
}

[jainuinelyselfish]

Awesomely simple! Best and clear-cut, to-the-point explanation, just the way it should be! Thanks a ton :)