A valid number can be split up into these components (in order):
'e' or 'E', followed by an integer.A decimal number can be split up into these components (in order):
'+' or '-').'.'.'.', followed by one or more digits.'.', followed by one or more digits.An integer can be split up into these components (in order):
'+' or '-').For example, all the following are valid numbers: ["2", "0089", "-0.1", "+3.14", "4.", "-.9", "2e10", "-90E3", "3e+7", "+6e-1", "53.5e93", "-123.456e789"], while the following are not valid numbers: ["abc", "1a", "1e", "e3", "99e2.5", "--6", "-+3", "95a54e53"].
Given a string s, return true if s is a valid number.
Example 1:
Input: s = "0" Output: true
Example 2:
Input: s = "e" Output: false
Example 3:
Input: s = "." Output: false
Constraints:
1 <= s.length <= 20s consists of only English letters (both uppercase and lowercase), digits (0-9), plus '+', minus '-', or dot '.'.