বিপিএসসি নন-ক্যাডার সিএসই (বিষয়ভিত্তিক) MCQ প্রশ্ন সমাধান ২০২৫ — প্রশ্ন ও সমাধান

ব্যাখ্যা: SUM is an aggregate function in SQL used to calculate the total of a numeric column. Other aggregate functions include COUNT, AVG, MIN, and MAX. WHERE, SELECT, and FROM are SQL clauses, not aggregate functions.

ব্যাখ্যা: A primary key is a field (or combination of fields) in a table that uniquely identifies each record. It cannot have NULL values and ensures data integrity. Foreign keys reference primary keys in other tables.

ব্যাখ্যা: Aggregate functions in databases perform calculations on multiple rows. SUM() is used to calculate the total of numeric values. Others include COUNT(), AVG(), etc.

ব্যাখ্যা: A Primary Key is used to uniquely identify each record in a database table. No two rows can have the same value for the primary key column(s).

ব্যাখ্যা: Quick sort uses the divide and conquer technique, dividing arrays into partitions recursively.

ব্যাখ্যা: In linear search, the algorithm may have to check every element once in the worst case, making it O(n).

ব্যাখ্যা: Stack follows the Last-In, First-Out (LIFO) principle, where the last inserted element is removed first.

ব্যাখ্যা: Heap sort is memory-efficient, requiring only constant space and no recursion, making it ideal for limited memory.

ব্যাখ্যা: Topological sorting is only valid for Directed Acyclic Graphs (DAGs) as they have no cycles and maintain dependency order.

ব্যাখ্যা: DFS uses a stack and generally consumes less memory than BFS, which requires storing a queue of nodes.

ব্যাখ্যা: A complete binary tree of height n can have up to 2ⁿ⁺¹ – 1 nodes. This includes all nodes from level 0 to level n completely filled.

ব্যাখ্যা: Arrays are used to store a collection of elements of the same type (e.g., all integers or all floats), which allows indexed access and efficient memory use.

ব্যাখ্যা: In an average case, searching in a balanced binary search tree (BST) takes O(log n) time, as it splits the tree in half each time. Worst-case complexity becomes O(n) if the tree becomes skewed (like a linked list).

ব্যাখ্যা: A postfix expression (also called Reverse Polish Notation) places operators after the operands. The correct structure doesn’t use parentheses and respects operator precedence. Example: abc*+de-+ = ((a + (b * c)) + (d - e))

ব্যাখ্যা: An adjacency list is a common data structure used to represent graphs. It stores a list of nodes and their neighbors, allowing efficient representation of sparse graphs.

ব্যাখ্যা: In C and most programming languages, an array stores elements of the same data type (e.g., all int or all float). This allows efficient indexing and memory management.

ব্যাখ্যা: A stack follows the Last In, First Out (LIFO) principle, meaning the last element added is the first to be removed. It supports operations like push() and pop(). It is used in recursion, expression evaluation, etc.

ব্যাখ্যা: A max heap is a binary tree where the root node contains the largest element. Every parent node is greater than or equal to its children, ensuring the maximum value is always at the root.

ব্যাখ্যা: Registers are the fastest type of memory, used directly by the CPU for immediate data processing.

ব্যাখ্যা: In 8-bit 2’s complement, 11111111 represents -1. To find the value, invert the bits and add 1. Invert: 00000000, Add 1: 00000001 → which is 1 in decimal. Therefore, the original number is -1.