Implementing Radix Sort Algorithm in C++

Radix sort is a non-comparison integer sorting algorithm that uses the least significant digit first (LSD) approach, sorting numbers digit by digit (units, tens, etc.) without comparing element sizes. Its core idea is to process each digit using a stable counting sort, ensuring that the result of lower-digit sorting remains ordered during higher-digit sorting. Implementation steps: 1. Identify the maximum number in the array to determine the highest number of digits to process; 2. From the lowest digit to the highest, process each digit using counting sort: count the frequency of the current digit, compute positions, place elements stably from back to front, and finally copy back to the original array. In the C++ code, the `countingSort` helper function implements digit-wise sorting (counting frequencies, calculating positions, and stable placement), while the `radixSort` main function loops through each digit. The time complexity is O(d×(n+k)) (where d is the maximum number of digits, n is the array length, and k=10), making it suitable for scenarios with a large range of integers. The core lies in leveraging the stability of counting sort to ensure that the results of lower-digit sorting are not disrupted during higher-digit sorting. Test results show that the sorted array is ordered, verifying the algorithm's effectiveness.