a=[1,2,3,100, 5, 6, 7]
workers=[[] for i in range(3)]
average = sum(a)//len(a)+1
 
# заполняем 1го работника
while ((sum(workers[0])+a[0])<=average) and (len(a)>2):
    workers[0].append(a[0])
    del a[0]
 
# если осталось 2 задачи, то раскидываем на остальных
if len(a)==2:
    workers[1].append(a[0])
    workers[2].append(a[1])
# если больше 2х задач, то аналогично заполняем 2го работника
else:
    while ((sum(workers[1])+a[0])<=average) and (len(a)>1):
        workers[1].append(a[0])
        del a[0]
    # заполняем 3го работника
    workers[2].extend(a)
 
print(*workers, end='\n')

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