folly::stable_radix_sort

template<typename ContiguousIt>
void
stable_radix_sort(
    ContiguousIt first,
    ContiguousIt last);

Description

Sorts elements using LSD radix sort. This is a stable sort: elements with equal keys preserve their original relative order.

Note: For floating-point types, the sort uses an augmented ordering equivalent to std::stable_sort(first, last, augmented_less) where:

template <std::floating_point T> struct augmented_less { bool operator()(T lhs, T rhs) const noexcept { if (lhs < rhs) return true; if (rhs < lhs) return false; return std::signbit(lhs) > std::signbit(rhs); } };

In other words, -0.0 sorts before +0.0. For all other values, the ordering matches operator<.

Requirements:

• ContiguousIt must be a contiguous iterator

• Value type must be floating-point or integral

Complexity: O(n * k) where k = sizeof(value_type) / 8 Space: O(n) for temporary buffer