class Solution {    public boolean isNumber(String s) {        s=s.trim();        int idx=s.indexOf('e');        if(idx>0)            return isNum(s.substring(0,idx), false)&&isNum(s.substring(idx+1), true);        return isNum(s, false);    }    private boolean isNum(String s, boolean dot){        if(s.length()==0)            return false;        int numlen=0;        for(int i=0;i
     
      ='0'&&s.charAt(i)<='9')                numlen++;            else if(i==0&&(s.charAt(i)=='+'||s.charAt(i)=='-'))                continue;            else if(s.charAt(i)=='.'&&dot==false)                dot=true;            else                return false;        }        return numlen>0;    }}