(defun calculate-level-sums (lst)
  (calculate-level-sums-helper lst 1 '()))
 
(defun calculate-level-sums-helper (lst level acc)
  (cond
    ((null lst) acc) ; Базовый случай: пустой список
    (t (multiple-value-bind (new-acc remaining-list)
           (process-level lst level acc)
         (calculate-level-sums-helper remaining-list level new-acc)))))
 
(defun process-level (lst level acc)
  (cond
    ((null lst) (values acc nil)) ; Базовый случай: пустой список, возвращаем аккумулятор и nil, как признак окончания
    ((numberp (car lst))
     (let ((new-acc (update-level-sum acc level (car lst))))
       (values new-acc (cdr lst)))) ; Обновляем аккумулятор и переходим к следующему элементу
    ((listp (car lst))
     (multiple-value-bind (inner-acc remaining-inner)
        (calculate-level-sums-helper (car lst) (1+ level) acc) ; Рекурсивно обрабатываем подсписок
      (values inner-acc (cdr lst)))); Возвращаем аккумулятор от подсписка и остаток исходного
    (t (values acc (cdr lst))))) ; Игнорируем не числовые атомы и продолжаем обработку
 
(defun update-level-sum (acc level value)
  (let ((existing (assoc level acc)))
    (if existing
        (let ((new-acc (remove existing acc :test #'equal)))
          (cons (list level (+ value (cadr existing))) new-acc))
        (cons (list level value) acc))))
 
(defun prepare-result (acc)
    (let ((has-level-one (assoc 1 acc)))
        (if has-level-one
          (sort acc #'< :key #'car)
          (sort (cons '(1 0) acc) #'< :key #'car))))
 
(defun calculate-level-sums (lst)
  (let ((acc '())) ; Initial accumulator
    (let ((result (calculate-level-sums-helper lst 1 acc)))
      (prepare-result result))))
 
 
; Тесты
(format t "~a~%" (calculate-level-sums '(a (b (4 (2 e (3) k 15) e 5) 7)))) ; ((1 0) (2 7) (3 9) (4 17) (5 3))
(format t "~a~%" (calculate-level-sums '(a b c))) ; ((1 0))
(format t "~a~%" (calculate-level-sums '(1 (2 (3))))) ; ((1 1) (2 2) (3 3))
(format t "~a~%" (calculate-level-sums '(1 2 (3 4 (5 6))))) ; ((1 3) (2 3) (3 10))

KGRlZnVuIGNhbGN1bGF0ZS1sZXZlbC1zdW1zIChsc3QpCiAgKGNhbGN1bGF0ZS1sZXZlbC1zdW1zLWhlbHBlciBsc3QgMSAnKCkpKQoKKGRlZnVuIGNhbGN1bGF0ZS1sZXZlbC1zdW1zLWhlbHBlciAobHN0IGxldmVsIGFjYykKICAoY29uZAogICAgKChudWxsIGxzdCkgYWNjKSA7INCR0LDQt9C+0LLRi9C5INGB0LvRg9GH0LDQuTog0L/Rg9GB0YLQvtC5INGB0L/QuNGB0L7QugogICAgKHQgKG11bHRpcGxlLXZhbHVlLWJpbmQgKG5ldy1hY2MgcmVtYWluaW5nLWxpc3QpCiAgICAgICAgICAgKHByb2Nlc3MtbGV2ZWwgbHN0IGxldmVsIGFjYykKICAgICAgICAgKGNhbGN1bGF0ZS1sZXZlbC1zdW1zLWhlbHBlciByZW1haW5pbmctbGlzdCBsZXZlbCBuZXctYWNjKSkpKSkKCihkZWZ1biBwcm9jZXNzLWxldmVsIChsc3QgbGV2ZWwgYWNjKQogIChjb25kCiAgICAoKG51bGwgbHN0KSAodmFsdWVzIGFjYyBuaWwpKSA7INCR0LDQt9C+0LLRi9C5INGB0LvRg9GH0LDQuTog0L/Rg9GB0YLQvtC5INGB0L/QuNGB0L7Quiwg0LLQvtC30LLRgNCw0YnQsNC10Lwg0LDQutC60YPQvNGD0LvRj9GC0L7RgCDQuCBuaWwsINC60LDQuiDQv9GA0LjQt9C90LDQuiDQvtC60L7QvdGH0LDQvdC40Y8KICAgICgobnVtYmVycCAoY2FyIGxzdCkpCiAgICAgKGxldCAoKG5ldy1hY2MgKHVwZGF0ZS1sZXZlbC1zdW0gYWNjIGxldmVsIChjYXIgbHN0KSkpKQogICAgICAgKHZhbHVlcyBuZXctYWNjIChjZHIgbHN0KSkpKSA7INCe0LHQvdC+0LLQu9GP0LXQvCDQsNC60LrRg9C80YPQu9GP0YLQvtGAINC4INC/0LXRgNC10YXQvtC00LjQvCDQuiDRgdC70LXQtNGD0Y7RidC10LzRgyDRjdC70LXQvNC10L3RgtGDCiAgICAoKGxpc3RwIChjYXIgbHN0KSkKICAgICAobXVsdGlwbGUtdmFsdWUtYmluZCAoaW5uZXItYWNjIHJlbWFpbmluZy1pbm5lcikKICAgICAgICAoY2FsY3VsYXRlLWxldmVsLXN1bXMtaGVscGVyIChjYXIgbHN0KSAoMSsgbGV2ZWwpIGFjYykgOyDQoNC10LrRg9GA0YHQuNCy0L3QviDQvtCx0YDQsNCx0LDRgtGL0LLQsNC10Lwg0L/QvtC00YHQv9C40YHQvtC6CiAgICAgICh2YWx1ZXMgaW5uZXItYWNjIChjZHIgbHN0KSkpKTsg0JLQvtC30LLRgNCw0YnQsNC10Lwg0LDQutC60YPQvNGD0LvRj9GC0L7RgCDQvtGCINC/0L7QtNGB0L/QuNGB0LrQsCDQuCDQvtGB0YLQsNGC0L7QuiDQuNGB0YXQvtC00L3QvtCz0L4KICAgICh0ICh2YWx1ZXMgYWNjIChjZHIgbHN0KSkpKSkgOyDQmNCz0L3QvtGA0LjRgNGD0LXQvCDQvdC1INGH0LjRgdC70L7QstGL0LUg0LDRgtC+0LzRiyDQuCDQv9GA0L7QtNC+0LvQttCw0LXQvCDQvtCx0YDQsNCx0L7RgtC60YMKCihkZWZ1biB1cGRhdGUtbGV2ZWwtc3VtIChhY2MgbGV2ZWwgdmFsdWUpCiAgKGxldCAoKGV4aXN0aW5nIChhc3NvYyBsZXZlbCBhY2MpKSkKICAgIChpZiBleGlzdGluZwogICAgICAgIChsZXQgKChuZXctYWNjIChyZW1vdmUgZXhpc3RpbmcgYWNjIDp0ZXN0ICMnZXF1YWwpKSkKICAgICAgICAgIChjb25zIChsaXN0IGxldmVsICgrIHZhbHVlIChjYWRyIGV4aXN0aW5nKSkpIG5ldy1hY2MpKQogICAgICAgIChjb25zIChsaXN0IGxldmVsIHZhbHVlKSBhY2MpKSkpCgooZGVmdW4gcHJlcGFyZS1yZXN1bHQgKGFjYykKICAgIChsZXQgKChoYXMtbGV2ZWwtb25lIChhc3NvYyAxIGFjYykpKQogICAgICAgIChpZiBoYXMtbGV2ZWwtb25lCiAgICAgICAgICAoc29ydCBhY2MgIyc8IDprZXkgIydjYXIpCiAgICAgICAgICAoc29ydCAoY29ucyAnKDEgMCkgYWNjKSAjJzwgOmtleSAjJ2NhcikpKSkKCihkZWZ1biBjYWxjdWxhdGUtbGV2ZWwtc3VtcyAobHN0KQogIChsZXQgKChhY2MgJygpKSkgOyBJbml0aWFsIGFjY3VtdWxhdG9yCiAgICAobGV0ICgocmVzdWx0IChjYWxjdWxhdGUtbGV2ZWwtc3Vtcy1oZWxwZXIgbHN0IDEgYWNjKSkpCiAgICAgIChwcmVwYXJlLXJlc3VsdCByZXN1bHQpKSkpCgoKOyDQotC10YHRgtGLCihmb3JtYXQgdCAifmF+JSIgKGNhbGN1bGF0ZS1sZXZlbC1zdW1zICcoYSAoYiAoNCAoMiBlICgzKSBrIDE1KSBlIDUpIDcpKSkpIDsgKCgxIDApICgyIDcpICgzIDkpICg0IDE3KSAoNSAzKSkKKGZvcm1hdCB0ICJ+YX4lIiAoY2FsY3VsYXRlLWxldmVsLXN1bXMgJyhhIGIgYykpKSA7ICgoMSAwKSkKKGZvcm1hdCB0ICJ+YX4lIiAoY2FsY3VsYXRlLWxldmVsLXN1bXMgJygxICgyICgzKSkpKSkgOyAoKDEgMSkgKDIgMikgKDMgMykpCihmb3JtYXQgdCAifmF+JSIgKGNhbGN1bGF0ZS1sZXZlbC1zdW1zICcoMSAyICgzIDQgKDUgNikpKSkpIDsgKCgxIDMpICgyIDMpICgzIDEwKSk=