Simple AF SparseSet in C++17

SparseSet.cpp

#include "SparseSet.h"

void SparseSet::insert(int64_t value)
{
    ASSERT(!contains(value));
    m_dense_array[m_dense_head] = value;
    m_sparse_array[value] = m_dense_head;
    m_dense_head++;
}

void SparseSet::remove(int64_t value)
{
    ASSERT(contains(value));
    int64_t dense_idx = m_sparse_array[value];
    int64_t last_idx = m_dense_head-1;
    if (dense_idx == last_idx)
    {
        m_dense_head--;
        return;
    }

    int64_t last_value = m_dense_array[last_idx];
    m_dense_array[dense_idx] = last_value;
    m_sparse_array[last_value] = dense_idx;
    m_dense_head--;
}

bool SparseSet::contains(int64_t value)
{
    int64_t dense_idx = m_sparse_array[value];
    return dense_idx < m_dense_head && m_dense_array[dense_idx] == value;
}

SparseSet.h

#pragma once

#include <vector>
#include "Assert.h"

struct SparseSet
{
    SparseSet(int64_t capacity) : m_dense_head(0), m_dense_array(capacity), m_sparse_array(capacity) {}

    void insert(int64_t value);
    void remove(int64_t value);
    bool contains(int64_t value);

    inline void clear() { m_dense_head = 0; }

    std::vector<int64_t>::iterator dense_begin() { return m_dense_array.begin();}
    std::vector<int64_t>::iterator sparse_begin() { return m_sparse_array.begin();}

    std::vector<int64_t>::iterator dense_end() { return m_dense_array.end();}
    std::vector<int64_t>::iterator sparse_end() { return m_sparse_array.end();}

private:
    int m_dense_head;

    std::vector<int64_t> m_dense_array;
    std::vector<int64_t> m_sparse_array;
};

Was just mucking around. 👍