Divide Array in Sets of K Consecutive Numbers
<p>Given an array of integers <code>nums</code> and a positive integer <code>k</code>, check whether it is possible to divide this array into sets of <code>k</code> consecutive numbers.</p>

<p>Return <code>true</code> <em>if it is possible</em>.<strong> </strong>Otherwise, return <code>false</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3,3,4,4,5,6], k = 4
<strong>Output:</strong> true
<strong>Explanation:</strong> Array can be divided into [1,2,3,4] and [3,4,5,6].
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [3,2,1,2,3,4,3,4,5,9,10,11], k = 3
<strong>Output:</strong> true
<strong>Explanation:</strong> Array can be divided into [1,2,3] , [2,3,4] , [3,4,5] and [9,10,11].
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3,4], k = 3
<strong>Output:</strong> false
<strong>Explanation:</strong> Each array should be divided in subarrays of size 3.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= k &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
</ul>

<p>&nbsp;</p>
<strong>Note:</strong> This question is the same as&nbsp;846:&nbsp;<a href="https://leetcode.com/problems/hand-of-straights/" target="_blank">https://leetcode.com/problems/hand-of-straights/</a>
Greedy; Array; Hash Table; Sorting
class Solution {
    public boolean isPossibleDivide(int[] nums, int k) {
        if (nums.length % k != 0) {
            return false;
        }
        Arrays.sort(nums);
        Map<Integer, Integer> cnt = new HashMap<>();
        for (int x : nums) {
            cnt.merge(x, 1, Integer::sum);
        }
        for (int x : nums) {
            if (cnt.getOrDefault(x, 0) > 0) {
                for (int y = x; y < x + k; ++y) {
                    if (cnt.merge(y, -1, Integer::sum) < 0) {
                        return false;
                    }
                }
            }
        }
        return true;
    }
}
