//判断是否回文
function huiwen(num){
    let mun = 0;
    let temp = num;
    let n =1;
    if(num<0 || (num%10 == 0 && num!=0))
        return false;
    while(mun<temp){
        mun = mun*10+temp%(n*10);
        temp = (temp-temp%10)/10;
        console.log(mun,temp)
        if(temp==mun){
            return true
        }
    }
    if(mun-mun%10==temp*10){
        return true
    }else{
        return false
    }
}