--SQL

 
SELECT z.submission_date,
       z.total_count,
       z.hacker_id,
       c.name
FROM
  (SELECT y.*,
          sum(CASE
                  WHEN y.rn = y.sub_date_cnt THEN 1
                  ELSE 0
              END) OVER (PARTITION BY submission_date) AS total_count,
          dense_rank() OVER (PARTITION BY submission_date
                             ORDER BY cnt DESC, hacker_id) AS rnk
   FROM
     (SELECT a.hacker_id,
             a.submission_date,
             x.rn,
             sum(CASE
                     WHEN a.submission_date = b.submission_date THEN 1
                     ELSE 0
                 END) AS cnt ,
             count(DISTINCT b.submission_date) AS sub_date_cnt
      FROM
        (SELECT Submission_date,
                rank() OVER (
                             ORDER BY Submission_date) AS rn
         FROM
           (SELECT DISTINCT submission_date
            FROM Submissions
            WHERE submission_date >= '2016-03-01'
              AND submission_date <= '2016-03-15'))x
      LEFT JOIN Submissions a ON a.Submission_date = x.Submission_date
      LEFT JOIN Submissions b ON a.hacker_id = b.hacker_id
      AND b.Submission_date <= a.submission_date
      GROUP BY a.hacker_id,
               a.submission_date,
               x.rn
      ORDER BY a.submission_date,
               sum(CASE
                       WHEN a.submission_date = b.submission_date THEN 1
                       ELSE 0
                   END) DESC , a.hacker_id) y) z
LEFT JOIN hackers c ON z.hacker_id = c.hacker_id
WHERE z.rnk = 1
ORDER BY submission_date ;