FINALTERM EXAMINATION
Spring 2010
CS301- Data Structures
Time: 90 min
M a r k s: 58
CS301 Question No: 1 ( M a r k s: 1 )
Which one of the following operations returns top value of the stack?
► Push
► Pop
► Top
► First
CS301 Question No: 2 ( M a r k s: 1 )
Compiler uses which one of the following in Function calls,
► Stack
► Queue
► Binary Search Tree
► AVL Tree
CS301 Question No: 3 ( M a r k s: 1 )
Every AVL is _________________
► Binary Tree
► Complete Binary Tree
► None of these
► Binary Search Tree
CS301 Question No: 4 ( M a r k s: 1 )
If there are 56 internal nodes in a binary tree then how many external nodes this binary tree will have?
► 54
► 55
► 56
► 57
CS301 Question No: 5 ( M a r k s: 1 )
If there are 23 external nodes in a binary tree then what will be the no. of internal nodes in this binary tree?
► 23
► 24
► 21
► 22
CS301 Question No: 6 ( M a r k s: 1 )
Which one of the following is not an example of equivalence relation?
► Electrical connectivity
► Set of people
►
► Set of pixels
CS301 Question No: 7 ( M a r k s: 1 )
Binary Search is an algorithm of searching, used with the ______ data.
► Sorted
► Unsorted
► Heterogeneous
► Random
CS301 Question No: 8 ( M a r k s: 1 )
Which one of the following is NOT true regarding the skip list?
► Each list Si contains the special keys + infinity and - infinity.
► List S0 contains the keys of S in non-decreasing order.
► Each list is a subsequence of the previous one.
► List Sh contains only the n special keys.
CS301 Question No: 9 ( M a r k s: 1 )
A simple sorting algorithm like selection sort or bubble sort has a worst-case of
► O(1) time because all lists take the same amount of time to sort
► O(n) time because it has to perform n swaps to order the list.
► O(n2) time because sorting 1 element takes O(n) time - After 1 pass through the list,
either of these algorithms can guarantee that 1 element is sorted.
► O(n3) time, because the worst case has really random input which takes longer to
sort.
CS301 Question No: 10 ( M a r k s: 1 )
Which of the following is a property of binary tree?
► A binary tree of N external nodes has N internal node.
► A binary tree of N internal nodes has N+ 1 external node.
► A binary tree of N external nodes has N+ 1 internal node.
► A binary tree of N internal nodes has N- 1 external node.
CS301 Question No: 11 ( M a r k s: 1 )
By using __________we avoid the recursive method of traversing a Tree, which makes use of stacks and consumes a lot of memory and time.
► Binary tree only
► Threaded binary tree
► Heap data structure
► Huffman encoding
CS301 Question No: 12 ( M a r k s: 1 )
Which of the following statement is true about dummy node of threaded binary tree?
► This dummy node never has a value.
► This dummy node has always some dummy value.
► This dummy node has either no value or some dummy value.
► This dummy node has always some integer value.
CS301 Question No: 13 ( M a r k s: 1 )
For a perfect binary tree of height h, having N nodes, the sum of heights of nodes is
► N – (h – 1)
► N – (h + 1)
► N – 1
► N – 1 + h
CS301 Question No: 14 ( M a r k s: 1 ) - Please choose vu zs one
What is the best definition of a collision in a hash table?
► Two entries are identical except for their keys.
► Two entries with different data have the exact same key
► Two entries with different keys have the same exact hash value.
► Two entries with the exact same key have different hash values.
CS301 Question No: 15 ( M a r k s: 1 )
Which formula is the best approximation for the depth of a heap with n nodes?
► log (base 2) of n
► The number of digits in n (base 10), e.g., 145 has three digits
► The square root of n
► n
CS301 Question No: 16 ( M a r k s: 1 )
Which of the following statement is NOT correct about find operation:
► It is not a requirement that a find operation returns any specific name, just that finds on two elements return the same answer if and only if they are in the same set.
► One idea might be to use a tree to represent each set, since each element in a tree has the same root, thus the root can be used to name the set.
► Initially each set contains one element.
► Initially each set contains one element and it does not make sense to make a tree of one node only.
CS301 Question No: 17 ( M a r k s: 1 )
Which of the following is not true regarding the maze generation?
► Randomly remove walls until the entrance and exit cells are in the same set.
► Removing a wall is the same as doing a union operation.
► Remove a randomly chosen wall if the cells it separates are already in the same set.
► Do not remove a randomly chosen wall if the cells it separates are already in the same set.
CS301 Question No: 18 ( M a r k s: 1 )
In threaded binary tree the NULL pointers are replaced by ,
► preorder successor or predecessor
► inorder successor or predecessor
► postorder successor or predecessor
► NULL pointers are not replaced
CS301 Question No: 19 ( M a r k s: 1 )
Which of the given option is NOT a factor in Union by Size:
► Maintain sizes (number of nodes) of all trees, and during union.
► Make smaller tree, the subtree of the larger one.
► Make the larger tree, the subtree of the smaller one.
► Implementation: for each root node i, instead of setting parent[i] to -1, set it to -k if tree rooted at i has k nodes.
CS301 Question No: 20 ( M a r k s: 1 )
Suppose we had a hash table whose hash function is “n % 12”, if the number 35 is already in the hash table, which of the following numbers would cause a collision?
► 144
► 145
► 143
► 148
CS301 Question No: 21 ( M a r k s: 1 )
What requirement is placed on an array, so that binary search may be used to locate an entry?
► The array elements must form a heap.
► The array must have at least 2 entries.
► The array must be sorted.
► The array’s size must be a power of two.
CS301 Question No: 22 ( M a r k s: 1 )
A binary tree with 24 internal nodes has ______ external nodes.
► 22
► 23
► 48
► 25
CS301 Question No: 23 ( M a r k s: 1 )
In case of deleting a node from AVL tree, rotation could be prolong to the root node.
► Yes
► No
CS301 Question No: 24 ( M a r k s: 1 )
when we have declared the size of the array, it is not possible to increase or decrease it during the ________of the program.
► Declaration
► Execution
► Defining
► None of the above
CS301 Question No: 25 ( M a r k s: 1 )
it will be efficient to place stack elements at the start of the list because insertion and removal take _______time.
► Variable
► Constant
► Inconsistent
► None of the above
CS301 Question No: 26 ( M a r k s: 1 )
_______ is the stack characteristic but _______was implemented because of the size limitation of the array.
► isFull(),isEmpty()
► pop(), push()
► isEmpty() , isFull()
► push(),pop()
CS301 Question No: 27 ( M a r k s: 2 )
Give the difference between strict and complete binary tree.
Ans:
A tree is a strictly binary tree if its each leaf node has non-empty left and right sub trees, and
If there are left and right sub-trees for each node in a binary tree is known as complete binary tree.
CS301 Question No: 28 ( M a r k s: 2 )
A complete binary tree can be stored in an array. While storing the tree in an array
we leave the first position (0th index )of the array empty. Why?
Ans
Because we need a pointer in an array to point a position of node of tree. parent node and the children nodes. In case of having a node with left and right children, stored at position i in the array, the left 2i and the right child will be at 2i+1 position. If the value of i 2, the parent will be at position 2 and the left child will be at position 2i i.e. 4 .The right child will be at position 2i+1 i.e. 5. we have not started the 0th position. It is simply due to the fact if the position is 0, 2i will also
become 0. So we will start from the 1st position, ignoring the 0th.
CS301 Question No: 29 ( M a r k s: 2 )
Give the name of two Divide and Conquer algorithms.
Ans:
- Merge sort
- Quick sort
- Heap sort
CS301 Question No: 30 ( M a r k s: 2 )
Give the effect of sorted data on Binary Search.
CS301 Question No: 31 ( M a r k s: 3 )
Give any three characteristics of Union by Weight method.
Ans:
1. This is also calles union by size.
- Maintain sizes (number of nodes) of all trees, and during union.
- Make smaller tree, the subtree of the larger one.
- for each root node i, instead of setting parent[i] to -1, set it
to -k if tree rooted at i has k nodes.
CS301 Question No: 32 ( M a r k s: 3 )
Here is an array of ten integers:
5 3 8 9 1 7 0 2 6 4
Draw this array after the FIRST iteration of the large loop in an insertion sort (sorting from smallest to largest). This iteration has shifted at least one item in the array!
CS301 Question No: 33 ( M a r k s: 3 )
Give your comment on the statement that heap uses least memory in array representation of binary trees. Justify your answer in either case.
CS301 Question No: 34 ( M a r k s: 5 )
Suppose we have the following representation for a complete Binary Search Tree, tell the Left and Right child nodes and Parent node of the node D
| |
| | | A | | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | …. |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | …. |
CS301 Question No: 35 ( M a r k s: 5 )
Explain the following terms:
1. Collision
2. Linear Probing
3. Quadratic Probing
Ans:
Collision:
it takes place when two or more keys (data items) produce the same index.
Linear Probing
when there is a collision, some other location in the array is found. This is known as linear probing. In linear probing, at the time of collisions, we add one to the index and check that location. If it is also not empty, we add 2 and check that position. Suppose we keep on incrementing the array index and reach at the end of the table. We were unable to find the space and reached the last location of the array.
Quadratic Probing
In the quadratic probing when a collision happens we try to find the empty location at
index + 12. If it is filled then we add 22 and so on.
Quadratic probing uses different formula:
- Use F(i) = i2 (square of i) to resolve collisions
- If hash function resolves to H and a search in cell H is inconclusive, try
H + 12, H + 22, H + 32
CS301 Question No: 36 ( M a r k s: 5 )
Here is an array with exactly 15 elements:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15.
Suppose that we are doing a binary search for an element. Indicate any elements that will be found by examining two or fewer numbers from the array.
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