Data Structures & STL

Question 1

int

Answer 1

Signed integer;
fast, common for counters, indices, quantities.

Question 2

uint

Answer 2

Non-negative integer;
useful for sizes, counts, bit manipulations.

Question 3

float/double

Answer 3

used for prices, computations requiring decimals.

Question 4

char

Answer 4

used in strings, parsing, small memory footprints.

Question 5

bool

Answer 5

true/false flags, conditional states.

Question 6

vector

Answer 6

Dynamic array; contiguous memory
Good for cache locality and fast iteration.

Question 7

deque

Answer 7

Double-ended queue
slightly less cache-friendly than vector.

Question 8

list

Answer 8

Doubly/singly linked list
Good for frequent insert/remove, but poor cache locality.

Question 9

array

Answer 9

Fixed-size array; stack-allocated, no dynamic resizing.
Useful for small fixed-size buffers or embedded contexts.

Question 10

string

Answer 10

Dynamic character sequence;
Widely used for identifiers, messages, parsing.
Associative Containers

Question 11

set

Answer 11

Ordered unique elements;
good for fast lookup and sorted data.

Question 12

map

Answer 12

Ordered key-value pairs;
good for dictionaries with sorted keys.

Question 13

unordered_set

Answer 13

Hash-based unique elements;
useful for fast membership tests.

Question 14

unordered_map

Answer 14

Hash-based key-value pairs;
good for fast lookups where ordering isn’t required.

Question 15

stack

Answer 15

LIFO structure;
Useful for undo operations, recursion emulation.

Question 16

queue

Answer 16

FIFO structure;
Good for task scheduling, event handling.

Question 17

priority_queue

Answer 17

Heap-based max/min queue;
useful for event scheduling, order books, or top-K elements.

Question 18

iterator

Answer 18

Object to traverse containers

Question 19

sort

Answer 19

Sort container elements;
Useful for ordered output or binary search prep.

Question 20

find

Answer 20

Linear search;
Simple element existence check.

Question 21

binary_search

Answer 21

Logarithmic search on sorted data;
Fast membership check.

Question 22

lower_bound / upper_bound

Answer 22

Binary search returning iterators;
useful for range queries in ordered containers.