题解 | #进制转换#

    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNext()){
            String str = scanner.nextLine();
            System.out.println(baseChange(str));
        }
    }

    private static int baseChange(String s){
        int i = s.length()-1;
        int res = 0;
        int pow = 0;
        while(i >= 2){
            char c = s.charAt(i);
            if(c >= 65){
                res += (c-55) * Math.pow(16, pow);
            }else{
                res += (c-48) * Math.pow(16, pow);
            }
            i--;
            pow++;
        }
        return res;
    }