Pattern

2 Rounds

1st OA --> Conginnitive Test

2nd OA--> Core Mcqs

MCQ 1
Q. Consider the following pseudocode:
x = 1, y = 7
For i = 1 to 4:
    ...
Print(x * y)

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MCQ 2
Q. What is the output after reversing the linked list?
Input:
1 -> 2 -> 3 -> NULL

A. 1 -> 2 -> 3 -> NULL
B. 2 -> 1 -> 3 -> NULL
C. 3 -> 2 -> 1 -> NULL
D. NULL -> 3 -> 2 -> 1

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MCQ 3
Q. What is the minimum Hamming distance required to detect and correct all single-bit errors?

A. 2
B. 3
C. 4
D. 5

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MCQ 4
Q. Which data structure is most suitable for representing a hierarchical file system?

A. Stack
B. Queue
C. Tree
D. Graph

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MCQ 5
Q. If a dynamic array grows by a factor of 1.5 instead of 2, what happens to the amortized complexity of the append operation?

A. O(1)
B. O(log N)
C. O(N)
D. O(N log N)

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MCQ 6
Q. Which technique is commonly used to detect cycles in a directed graph representing course prerequisites?

A. BFS using a queue
B. DFS with recursion stack (back-edge detection)
C. Binary Search
D. Union-Find

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MCQ 7
Q. Which statement about Kahn's Algorithm is correct?

A. It uses DFS recursion.
B. It repeatedly removes vertices with in-degree zero; if fewer than V vertices are processed, the graph contains a cycle.
C. It works only on undirected graphs.
D. It finds shortest paths.

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MCQ 8
Q. What is the time complexity of merging k sorted lists containing n total elements using a min-heap?

A. O(n)
B. O(n log n)
C. O(n log k)
D. O(k log n)

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MCQ 9
Q. What is the time complexity of the following pseudocode?

for i = 1 to N
    j = i
    while j > 0
        j = j / 2

A. O(N)
B. O(N log N)
C. O(log N)
D. O(N²)

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MCQ 10
Q. Determine the complexity of:

for i = 1 to N
    j = 1
    while j < N
        j = j * (2 * i)

A. O(log N)
B. O(N)
C. O(N log N)
D. O(N²)

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MCQ 11
Q. What is the time complexity of Strassen's Matrix Multiplication?

A. O(n²)
B. O(n²·log n)
C. O(n^(log₂7))
D. O(n³)

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MCQ 12
Q. Determine the complexity:

for i = 1 to N
    j = 1
    while j <= N
        j += 3

A. O(N)
B. O(log N)
C. O(N log N)
D. O(N²)

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MCQ 13
Q. Solve the recurrence:

T(N) = 2T(N/3) + O(1)

A. O(log N)
B. O(N)
C. O(N^(log₃2))
D. O(N log N)

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MCQ 14
Q. Determine the complexity:

for i = 0 to N-1
    if i % 100 == 0
        for j = 0 to N-1

A. O(N)
B. O(N log N)
C. O(N²)
D. O(N³)

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MCQ 15
Q. Each iteration copies an array and sorts it.

for i = 1 to N
    copy array
    sort array

What is the time complexity?

A. O(N)
B. O(N log N)
C. O(N²)
D. O(N² log N)

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MCQ 16
Q. A min-heap repeatedly performs extractMin() until empty. What is the total complexity?

A. O(N)
B. O(log N)
C. O(N log N)
D. O(N²)

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MCQ 17
Q. What is the complexity of DFS using an adjacency matrix?

A. O(V + E)
B. O(E²)
C. O(V²)
D. O(V log V)

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MCQ 18
Q. Solve the recurrence:

T(N) = 5T(N/2) + O(1)

A. O(N²)
B. O(N^(log₂5))
C. O(N log N)
D. O(log N)

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MCQ 19
Q. Which data structure is best for a scheduler that always executes the highest-priority task efficiently?

A. List
B. Max Heap (Priority Queue)
C. Sorted Array
D. HashMap

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MCQ 20
Q. Which structure is used in Skip Lists?

A. Single pointer
B. Array of forward pointers
C. Parent pointer
D. Circular pointer

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MCQ 21
Q. Which technique provides approximate distinct counting with very low memory?

A. HashSet
B. Bloom Filter
C. HyperLogLog
D. Trie

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MCQ 22
Q. Which algorithm is most efficient for finding all prime numbers up to N?

A. Naive trial division
B. Trial division up to √N
C. Sieve of Eratosthenes
D. Trial division using known primes

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MCQ 23
Q. Why does Small-to-Large Merging (DSU on Tree) achieve O(N log N)?

A. It uses binary search.
B. Each element moves only into a set at least twice as large.
C. It compresses the tree into a linked list.
D. It avoids recursion completely.

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MCQ 24
Q. Which data structure is best suited for a large distributed Peer-to-Peer file-sharing system?

A. Local list
B. Central server
C. Distributed Hash Table (DHT)
D. Broadcast queries

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MCQ 25
Q. Which recurrence counts the number of distinct Max-Heaps on n distinct keys?

A. f(n) = f(n−1) + n
B. f(n) = 2f(n/2)
C. f(n) = C(n−1,L) × f(L) × f(R)
D. f(n) = n!

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MCQ 26
Q. Which data structure combination implements an O(1) LRU Cache?

A. Array
B. HashMap + Queue
C. HashMap + Doubly Linked List
D. HashMap + Heap

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MCQ 27
Q. Which version-control storage approach is the most efficient?

A. Store complete copy of every version
B. Linked list of versions
C. DAG with content-addressable storage (Git-style)
D. Flat file of changes