UGC NET Computer Science Data Structures Previous Year Questions (PYQs) – Page 1 of 9

Using Kruskal's algorithm, edges are selected in increasing order of weight.

From the graph:

$a-b = 1$

$d-f = 1$

$b-f = 2$

$d-c = 2$

$d-e = 3$

So, the valid order must follow:

Weight $1$ edges first:

$I, II$ in any order

Then weight $2$ edges:

$III, IV$ in any order

Then weight $3$ edge:

$V$

Now check option (c):

II, I, III, V, IV

Here, edge $V = d-e$ has weight $3$, but edge $IV = d-c$ has weight $2$.

So, selecting $V$ before $IV$ violates Kruskal's increasing weight rule.

Therefore, this order cannot be used.

Insert words sequentially into BST.

banana → root

peach → right of banana

apple → left of banana

pear → right of peach

coconut → left of peach

mango → right of coconut

papaya → right of mango

Longest path:

banana → peach → coconut → mango → papaya

Number of edges = 4

For a 3D array $A[a][b][c]$ stored in row major order:

Address of $A[r][s][t]$ is

Base address + $w[(r \times b \times c) + (s \times c) + t]$

So,

Address = $ A[0][0][0] + w(bcr + c*s + t)$

• An adjacency matrix represents a graph using a 2D array (matrix).
• This type of storage uses sequential memory allocation — rows and columns are stored in contiguous memory.
• Hence, this method is called a Sequential Representation of a graph.

Statement I is incorrect because if f = O(g), then f grows no faster than g. So, g is not smaller than f.

Statement II is also incorrect because exponential time is generally represented as exponential in input size, not O(2^k) where k is a constant.