Skip to main content

Link List

9. Find whether a list is even or odd.
10. Reverse a link list with/without recursion.
11. Shuffle two link list of same size.
12. Merge two sorted link list.
13. Find whether two list are intersecting or not.
14. Detect a loop in link list.
15. Remove loop from link list.
16. Find the length of loop.
17. Find the kth element from end.

Comments

  1. 9. Find whether a list is even or odd.
    a) Keep counting.
    b) Use a bool for flag
    c) Without any variable
    int isOdd ( struct node *head )
    {
    Head = head->next;
    While ( head)
    {
    If ( head->next == NULL )
    Return 1;
    Head = head->next->next;
    }
    }
    10. Reverse a link list with/without recursion.
    Void reverselist( struct node *head )
    {
    Struct node *prev, *current, *temp;
    Prev = NULL;
    Current = head->next;
    While ( current )
    {
    Temp = current->next;
    Current->next = prev;
    Prev = current;
    Current = temp;
    }
    Head->next = prev;
    }

    11. Shuffle two link list of same size. If p and q are head pointers.
    Struct node *newhead = p;
    While (q )
    {
    Swap(&p->next, &q);
    P = p->next;
    }
    12. Merge two sorted link list.
    13. Find whether two list are intersecting or not.
    a) Use negation technique. Traverse list 1 and negate elements. Traverse list 2 and return first negated element.
    b) Hashtable: insert node in hashtable. If found collision return element.
    c) Length of list 1 = m length of list 2 = n. Traverse |m-n| element and then start comparing.
    14. Detect a loop in link list.
    a) Maintain a flag for each node visited. If you see any node already visited then a loop.
    b) use hashtable for nodes.
    c) Take two pointers. Increment first by one and another by two.
    Note: Application kernel programming and random number generator.

    15. Remove loop from link list.
    Use the loop detection approach and as soon as you know node->next is repeated, make it null.
    16. Find the length of loop.
    Use any of the above three approach and keep a counter until a node repeated.
    17. Find the kth element from end.
    a) Bruteforce: count the list nodes once and go for the (n-k) node next time.
    b) Maintain two pointer, both pointing to I and i-k node. So when pointer 1 point at n second one will point to n-k.

    ReplyDelete

Post a Comment

Popular posts from this blog

Car Parking Problem

There is n parking slots and n-1 car already parked. Lets say car parked with initial arrangement and we want to make the car to be parked to some other arrangement. Lets say n = 5, inital = free, 3, 4, 1, 2 desired = 1, free, 2, 4 ,3 Give an algorithm with minimum steps needed to get desired arrangement. Told by one of my friend and after a lot of search i really got a nice solution. I will post solution in comment part

DEShaw Interview Questions

ther are N numbers frm 1 to N and starting from index 1 we will keep deleting every alternate going in cyclic order with array. Only one element will be left at the end. Tell us the index of element in array we started. e.g. there are 5 nums 1 2 3 4 5 then after 1st iteration 1 3 5 will be remained. .. then 1 will be next to be elliminated and then 5 3 will remain alone... give sum efficient algorithm to calculate which numer will remain at the end Answer: 2*(n-2^p)+1 where p=floor(log2 n)

[Tree]..Is parent or grandparent?

There are two nodes given in a tree(not binary tree). Find whether one node is parent/grand parent of other. order should be O(1). tag root as 0 , tag left child as 00 , right child as 01. left child's left child as 000 , left's child's right child as 001 ... and so on. now let input be tags t1 and t2 if( (t1 == (t2>>1)) || (t2==(t1>>1))) return child parent relationship if( (t1 == (t2>>2)) || (t2==(t1>>2))) return child grand-parent relationship ... This solution can take a lot of space as the three grows. We can tag the node by number .. Root -0 1 -2-3-4 SO given two node get their tags.. Get Max of both t1, t2. Go for parent of that node if other node then return or check for parent of parent and check again for other node. With 2^32 value avaialable for indexing ..u wont run out of values.