Category: Data Structure

both Rust and C++ basically give you two big “map families”:

• ordered map (tree-based): keys kept sorted, predictable iteration order
• unordered map (hash-based): keys not sorted, usually faster average lookups

What an ordered map actually is

BTreeMap (Rust) and std::map (C++) are not arrays.

They are balanced trees (B-tree …

1) FIFO Queue (the classic queue)

Rule:
First In → First Out

append back, pop from front

Like people waiting for coffee.

enter:  A B C D
leave:  A B C D

Operations:

enqueue  (add at back)
dequeue  (remove from front)

Rust implementation

Use:

VecDeque

use std::collections::VecDeque;

let mut q