leetcode 65. Valid Number

Validate if a given string is numeric.

Some examples:
“0” => true
” 0.1 ” => true
“abc” => false
“1 a” => false
“2e10” => true
Note: It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one.

Update (2015-02-10):
The signature of the C++ function had been updated. If you still see your function signature accepts a const char * argument, please click the reload button to reset your code definition.

正则表达式大法：
“^(-|\+)?[0-9]+(\.[0-9]*)?(e(-|\+)?[0-9]+)?”“(−|\+)?\.[0−9]+(e(−|\+)?[0−9]+)?”

public boolean isNumber(String s) {        s = s.trim();        String pattern1 = "^(-|\\+)?[0-9]+(\\.[0-9]*)?(e(-|\\+)?[0-9]+)?$";        String pattern2 = "^(-|\\+)?\\.[0-9]+(e(-|\\+)?[0-9]+)?$";        //System.out.println(s +" " +s.matches(pattern1)+" " + s.matches(pattern2));        System.out.println(s);        return s.matches(pattern1) || s.matches(pattern2);    }