[프로그래머스/Java] 다항식 더하기

-Code

class Solution {
    public String solution(String polynomial) {
        int x_val = 0, num_val = 0;
        for (String s : polynomial.split(" ")) {
            if (s.equals("+")) continue;

            if (s.charAt(s.length() - 1) == 'x') {
                x_val += s.length() != 1 ?
                        Integer.parseInt(s.substring(0, s.length() - 1)) :
                        1;
            } else {
                num_val += Integer.parseInt(s);
            }
        }

        String x_string = (x_val == 0 ? "" : (x_val == 1 ? "x" : x_val + "x"));
        String num_string = (num_val == 0 ? "" : "" + num_val);
        String plus = x_val == 0 || num_val == 0 ? "" : " + ";
        return  x_string + plus + num_string;
    }
}