def solution(n, t, m, timetable):
timetable = [int(tt.split(":")[0]) * 60 + int(tt.split(":")[1]) for tt in timetable] timetable.sort() bus = [540 + t*i for i in range(n)] lists = [] for b in bus: cnt = 0 flag = 0 for t in timetable: if t <= b and cnt < m: lists.append(timetable.pop(0)) cnt += 1 else: break ; if cnt == m: flag = 1
if flag == 1:
time = lists[-1] - 1
else:
time = bus[-1]
return '%02d:%02d' % (time // 60, time % 60)