Match scientific notation

Write a regex that validates strings as scientific notation numbers.

regex validation scientific-notation

Write a function `is_scientific_notation(s: str) -> bool` that returns `True` if the string `s` represents a valid scientific notation number, and `False` otherwise.

A valid scientific notation number is defined as:
- an optional sign (`+` or `-`),
- followed by a decimal number (an integer part and optionally a fractional part), where the integer part is always present,
- followed by the exponent marker `e` or `E`,
- followed by an optional sign and an integer exponent (at least one digit).

More precisely, the string must match the pattern: `[+-]?` then `(digits ( '.' digits? )? | '.' digits )` then `[eE]` then `[+-]?` then `digits`.

Note that the decimal number must have digits – it cannot be just a dot. The exponent part is mandatory. The function should use regular expressions.

Constraints

- The input string `s` may be empty or contain up to 100 characters.
- The function must use the `re` module (import is allowed).
- No leading/trailing whitespace is allowed in the input.
- Complexity: O(len(s)).

Example

>>> is_scientific_notation('1e10')
True
>>> is_scientific_notation('-1.2E-3')
True
>>> is_scientific_notation('.5e2')
True
>>> is_scientific_notation('1e')
False
>>> is_scientific_notation('1.2')
False

10 points ~15 min

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Hints

Use `re.fullmatch` with a pattern that includes `^` and `$` anchors.

Remember to escape the dot in the decimal part if you use it literally, but you can use character classes too.

Break the pattern: optional sign, decimal part, exponent marker, optional sign, exponent digits.

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