HashMap and BTreeMap for Key-Value Storage

HashMap and BTreeMap for Key-Value Storage

use std::collections::{HashMap, BTreeMap};

fn main() {
    // HashMap (O(1) average lookup)
    let mut map = HashMap::new();
    map.insert("order_1", 450);
    map.insert("order_2", 890);

    println!("Order 1 total: {:?}", map.get("order_1"));

    // BTreeMap (sorted keys, O(log N))
    let mut btree = BTreeMap::new();
    btree.insert(200, "Two Hundred");
    btree.insert(100, "One Hundred");

    for (k, v) in &btree {
        println!("Key {} -> {}", k, v);
    }
}