code: public static String[] unique(String[] arrays) {
          List<String> list = new ArrayList<>(arrays.length);
          for (String arr : arrays) {
              if (!list.contains(arr)) {
                  list.add(arr);
              }
          }
          String[] res = new String[list.size()];
          int i = 0;
          for (String arr : list) {
              res[i++] = arr;
          }
          return res;
      }
docs: 去重
  
  @param arrays 数组
  
  @return 去重后的数组