Student List for Course

def solve(nk, students_data, k_val):
    n, k_total = map(int, str(nk).split())
    k = int(k_val)
    course_students = {}
    for rec in str(students_data).strip().split(';'):
        parts = rec.split(':')
        name = parts[0].strip()
        if len(parts) > 1 and parts[1].strip():
            courses = list(map(int, parts[1].split(',')))
        else:
            courses = []
        for c in courses:
            if c not in course_students:
                course_students[c] = []
            course_students[c].append(name)
    for c in range(1, k + 1):
        students = sorted(course_students.get(c, []))
        print(f'{c} {len(students)}')
        for s in students:
            print(s)