# Decimal Radix Sort

## Description

Sort nonnegative integers in nondecreasing order by stable decimal-digit bucket passes.

## Input

The function receives an integer array `a` and its length $n$.

## Output

The same array contains the input values in nondecreasing order.

## Constraints

- $0 \le n \le 1000$.
- $0 \le a_i \le 999999999$ for every element.

## Source

Classical radix-sort problem reconstructed from the verified C artifact.