846. Hand of Straights

846. Hand of Straights

Alice has a hand of cards, given as an array of integers.

Now she wants to rearrange the cards into groups so that each group is size W, and consists of W consecutive cards.

Return true if and only if she can.

Example 1:

Input: hand = [1,2,3,6,2,3,4,7,8], W = 3
Output: true
Explanation: Alice's hand can be rearranged as [1,2,3],[2,3,4],[6,7,8].

Example 2:

Input: hand = [1,2,3,4,5], W = 4
Output: false
Explanation: Alice's hand can't be rearranged into groups of 4.

Note:

1. 1 <= hand.length <= 10000
2. 0 <= hand[i] <= 10^9
3. 1 <= W <= hand.length

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暴解

class Solution {
    public boolean isNStraightHand(int[] hand, int W) {
        int n = hand.length;
        Arrays.sort(hand);
        TreeMap<Integer, Integer> tree = new TreeMap<>();
        
        for (int i : hand) {
            tree.put(i, tree.getOrDefault(i, 0) + 1);
        }
        
        while (!tree.isEmpty()) {
            int count = 0, i = tree.firstKey();
            while (count < W) {
                if (!tree.containsKey(i)) return false;
                tree.put(i, tree.get(i) - 1);
                if (tree.get(i) == 0) tree.remove(i);
                i++;
                count++;
            }
        }
        
        return true;
    }
}