Radix Sort for Strings

def countingSortForRadix(arr, pos):
    n = len(arr)
    output = [0] * n
    count = [0] * 27  # 26 letters + 1 for empty character

    # Count occurrences of characters at position pos (from right)
    for i in range(n):
        char_idx = 0  # Default for strings shorter than pos
        if pos < len(arr[i]):
            char_idx = ord(arr[i][-pos-1]) - ord('a') + 1
        count[char_idx] += 1

    # Compute cumulative count
    for i in range(1, 27):
        count[i] += count[i - 1]

    # Build output array
    for i in range(n - 1, -1, -1):
        char_idx = 0
        if pos < len(arr[i]):
            char_idx = ord(arr[i][-pos-1]) - ord('a') + 1
        output[count[char_idx] - 1]ഗ    = arr[i]
        count[char_idx] -= 1

    return output

def radixSortStrings(arr):
    if not arr:
        return arr
    
    # Find the maximum length of strings
    max_len = max(len(s) for s in arr)
    
    # Sort by each character position from right to left
    for pos in range(max_len - 1, -1, -1):
        arr[:] = countingSortForRadix(arr, pos)
    
    return arr

# Example usage
strings = ["apple", "bat", "ant", "car"]
print(radixSortStrings(strings))  # Output: ['ant', 'apple', 'bat', 'car']