em>parallel_flat_hash_map</em> or <em>parallel_flat_hash_set</em>. It does provide the same external API as Abseil's other hash tables, and internally it uses a std::array of N <em>flat_hash_maps</em>.</p>
<p>I was delighted to find out that not only the <em>parallel_flat_hash_map</em> has significant memory usage benefits compared to the <em>flat_hash_map</em>, but it also has significant advantages for concurrent programming as I will show later.</p>
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<p>I will use the names <em>parallel_hash_