Growing a Dynamic Array

A dynamic array such as C++ std::vector stores its elements in one block of memory. When the block is full and a new element arrives, it allocates a block twice as large, copies the existing elements over, and frees the old one.

Start with an empty array of capacity initial_capacity and push pushes elements one by one. Before each push, if size == capacity, reallocate: count one reallocation, add the current size to the copied elements, and double the capacity.

Implement dynamic_array_growth(pushes, initial_capacity).

Input

pushes: How many elements are pushed.

initial_capacity: The capacity of the empty array.

Output

Return [reallocations, copied_elements, final_capacity].

Contraintes

0 ≤ pushes ≤ 10^7

1 ≤ initial_capacity ≤ 10^6

Exemples

Entrée :
pushes = 5
initial_capacity = 1

Sortie attendue :
expected = [3, 7, 8]

Entrée :
long long pushes = 5;
long long initial_capacity = 1;

Sortie attendue :
std::vector<long long> expected = {3, 7, 8};

Entrée :
long pushes = 5;
long initial_capacity = 1;

Sortie attendue :
long[] expected = new long[] {3, 7, 8};

Entrée :
pushes = 4
initial_capacity = 4

Sortie attendue :
expected = [0, 0, 4]

Entrée :
long long pushes = 4;
long long initial_capacity = 4;

Sortie attendue :
std::vector<long long> expected = {0, 0, 4};

Entrée :
long pushes = 4;
long initial_capacity = 4;

Sortie attendue :
long[] expected = new long[] {0, 0, 4};

Références

Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.

• cppreference, std::vector