89 lines
2.9 KiB
Python
89 lines
2.9 KiB
Python
from decimal import Decimal, InvalidOperation
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COUNT = 20
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HEADER = "Лабораторная работа №1"
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TASK = "Задача: найти максимальный элемент списка и поменять его с первым"
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FORMAT_HINT = "Можно вводить числа в формате: 10, -5.3, 1e20\n"
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def parse_number(user_input: str) -> tuple[Decimal, bool]:
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normalized = user_input.strip()
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if normalized == "":
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raise ValueError("Ошибка: пустой ввод. Повторите.")
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used_scientific = "e" in normalized.lower()
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normalized = normalized.replace(",", ".")
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try:
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number = Decimal(normalized)
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except InvalidOperation as error:
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raise ValueError("Ошибка: это не число. Попробуйте снова.") from error
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if not number.is_finite():
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raise ValueError("Ошибка: число должно быть конечным.")
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return number, used_scientific
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def collect_numbers(count: int) -> list[tuple[Decimal, bool]]:
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numbers: list[tuple[Decimal, bool]] = []
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while len(numbers) < count:
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raw_value = input(f"Введите число №{len(numbers) + 1}: ")
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try:
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numbers.append(parse_number(raw_value))
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except ValueError as error:
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print(error)
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return numbers
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def swap_first_with_max(numbers: list[tuple[Decimal, bool]]) -> tuple[tuple[Decimal, bool], int]:
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values = [value for value, _ in numbers]
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max_value = max(values)
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max_index = values.index(max_value)
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max_number = numbers[max_index]
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numbers[0], numbers[max_index] = numbers[max_index], numbers[0]
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return max_number, max_index
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# Красивый вывод Decimal без лишних нулей
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def format_decimal(value: Decimal) -> str:
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normalized = value.normalize()
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# Если число целое
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if normalized == normalized.to_integral():
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return str(normalized.quantize(Decimal(1)))
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return format(normalized, 'f').rstrip('0').rstrip('.')
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def format_number(value: Decimal, used_scientific: bool) -> str:
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if used_scientific:
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return f"{value.normalize():e}".replace("e+0", "e+").replace("e-0", "e-")
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return format_decimal(value)
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def format_number_list(numbers: list[tuple[Decimal, bool]]) -> str:
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return "[" + ", ".join(format_number(v, sci) for v, sci in numbers) + "]"
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def main() -> None:
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print(HEADER)
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print(TASK)
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print(FORMAT_HINT)
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numbers = collect_numbers(COUNT)
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print("\nИсходный список:", format_number_list(numbers))
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max_number, max_index = swap_first_with_max(numbers)
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print("Максимальный элемент:", format_number(*max_number))
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print("Индекс максимального элемента:", max_index)
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print("\nСписок после обмена:", format_number_list(numbers))
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if __name__ == "__main__":
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main()
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