def is_conflict(time1, time2):

"""Check if two time slots conflict."""

return time1[0] <= time2[1] and time2[0] <= time1[1]

def assign_courses(teacher_timeslots, courses):

"""Assign courses to teachers without conflicts."""

assigned = {}

for course in courses:

for teacher, times in teacher_timeslots.items():

valid_times = [t for t in times if not any(is_conflict(t, x) for x in assigned.get(teacher, []))]

if valid_times:

assigned.setdefault(teacher, []).append(valid_times[0])

break

return assigned