java实现将指定字符串替换为制定长度的空格

package try1;import java.util.LinkedList;import java.util.Queue;import java.util.Scanner;public class answer {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int x = sc.nextInt();// 组数Queue<String> q = new LinkedList<>();for (int i = 0; i < x; i++) {int a = sc.nextInt();// 每组的行数String[] s = new String[a];int b = sc.nextInt();// 替换成空格的个数for (int j = 0; j < s.length; j++) {s[j] = sc.next();}String[] n = dd(s, b);for (int j = 0; j < n.length; j++) {q.offer(n[j]);}}for (String string : q) {System.out.println(string);}}static String[] dd(String[] s, int b) {String a = "->";//这里是想要替换的字符串String[] n = new String[s.length];String m = new String();for (int i = 0; i < b; i++) {m += " ";}for (int i = 0; i < s.length; i++) {if (s[i].contains(a)) {s[i] = s[i].replaceAll(a, m);}n[i] = s[i];}return n;}}