public class MaxConsecutiveSum {
  
  public static class ConsecutiveInts {
    public final int start;
    public final int numElements;
    
    public ConsecutiveInts(int start, int numElements) {
      this.start = start;
      this.numElements = numElements;
    }
    
    public int[] asIntArray() {
      int[] result = new int[numElements];
      for (int i = 0; i < numElements; i++) {
        result[i] = start + i;
      }
      return result;
    }
  }
  public static ConsecutiveInts maxConsecutiveSumHelper(int num){
    // Can only use positive integers, so anything less than 1 won't work.
    if (num < 1) {
      return new ConsecutiveInts(0, 0);
    }
    int start = 1; //  current lowest possible number in the consecutive integers
    long sum = 0; // Use a long to avoid overflow.
    // Largest possible sum of at least 2 consecutive would be (num/2) + (num/2 + 1).
    final int highestPossible = Math.min(num, (num / 2) + 2);
    for (int i = 1; i < highestPossible; i++) {
      sum += i;
      // If our sum exceeds the target, start chopping off the smallest numbers.
      while (sum > num) {
        sum -= start;
        start++;
      }
      if (sum == num) {
        return new ConsecutiveInts(start, i - start + 1);
      }
      // else, sum < num, so keep going.
    }
    // No two consecutive integers below num.
    return new ConsecutiveInts(0, 0);
  }
  
  public static int[] maxConsecutiveSum(int num){
    return maxConsecutiveSumHelper(num).asIntArray();
  }
}