std::unorde...map::reserve(3)

okay bestie, buckle up: this is std::unorde...map::reserve(3) from the C++ Standard Libary manual 💅✨ (yes, “Libary,” she said what she said 🎀).

💖 NAME 💖

std::unordered_map::reserve — std::unordered_map::reserve (it’s giving “same name, same energy,” and honestly? iconic 💀).

✨ Synopsis ✨

void reserve( size_type count );  (since C++11)

okay so what does it actually do? It sets the number of buckets to the number needed to accommodate at least count elements without exceeding maximum load factor, and it rehashes the container — i.e. it puts the elements into appropriate buckets considering that the total number of buckets has changed. Effectively calls rehash(std::ceil(count / max_load_factor())). no cap, that’s the whole vibe 🦋

🌸 Parameters 🌸

• count — the new capacity of the container, bestie. That’s the number we’re reserving room for.

🎀 Return value 🎀

(none) — literally nothing comes back. void behavior, no notes, periodt 💅.

🦋 Complexity 🦋

Average case is linear in the size of the container, but worst case? quadratic 😭. So like, don’t get caught sleeping on the worst case, okay?

🌈 See also 🌈

• rehash — reserves at least the specified number of buckets and regenerates the hash table (public member function). bestie behavior, fr fr 🫶.

xoxo, source: http://cppreference.com, dated 2024.06.10 — from the std::unorde...map::reserve(3) page in the C++ Standard Libary manual 💖🧚