HandOfStraights.java

/* https://leetcode.com/problems/hand-of-straights/?envType=daily-question&envId=2024-06-06 */
/* 846. Hand of Straights */

class HandOfStraights {
    public boolean isNStraightHand(int[] hand, int groupSize) {
    TreeMap<Integer, Integer> count = new TreeMap<>();

    for (final int card : hand)
      count.merge(card, 1, Integer::sum);

    for (final int start : count.keySet()) {
      final int value = count.getOrDefault(start, 0);
      if (value > 0)
        for (int i = start; i < start + groupSize; ++i)
          if (count.merge(i, -value, Integer::sum) < 0)
            return false;
    }

    return true;
    }
}