codewars024: How Many Numbers? II

package codewars;
//--https://www.codewars.com/kata/55f5efd21ad2b48895000040/train/java
import java.util.*;
public class MaxSumDigits{
  private static Boolean valid(long num, int maxsm){
  String str = String.valueOf(num);
  for(int i = 0; i <= str.length() - 4; i++){
    int sum = 0;
    for(int j = i; j < i+4; j++){
      sum += str.charAt(j) - '0';
      if(sum > maxsm){
        return false;
      }
    }
  }
  return true;
  }
  
  public static long[] maxSumDig(long nmax, int maxsm){
    List<Long> list = new ArrayList<Long>();
    for(long i = 1000; i <= nmax; i++){
      if(MaxSumDigits.valid(i, maxsm)){
        list.add(i);
      }
    }
    long sum = 0;
    for(Long x : list){
      sum += x;
    }
    long mean = sum / list.size();
    long nearest = 0;
    if(list.contains(means)){
      nearest = mean;
    }else{
      for(int i=0; i<list.size(); i++){
        long temp = list.get(i);
        if(temp < mean){
          continue;
        }else{
          nearest = temp - mean > mean - list.get(i - 1) ? list.get(i - 1) : temp;
          break;
        }
      }
    }
    return new long[]{list.size(), nearest, sum};
  }
}