Difference in conditions

[lcs2019022]

if i m writing

while( fast->link!=NULL && fast!=NULL )

{

    fast=fast->link->link;

    slow=slow->link;

}

i m not getting ans when number of nodes is even but getting when number of nodes is odd .

but if i write

while(fast!=NULL && fast->link!=NULL)
{

    fast=fast->link->link;

    slow=slow->link;

}

i m getting right answers for both.

Can u explain WHY?

[pratyush63 (Pratyush Kumar)]

The condition fast!=Null should be placed before fast->link!=Null because if fast is NULL then fast->link will cause error in the program.

Linked list Midpoint

If you first keep fast->next != NULL in the condition this will cause segmentation fault. Consider a case when fast= NULL… so again in the loop condition fast->next is being performed which will give a segmentation fault. So the order must be (fast != NULL && fast->next != NULL When the first condition is false in case of && ,the second condition is not checked…

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