<p>Given an integer array <code>nums</code> and an integer <code>k</code>, return <code>true</code> if it is possible to divide this array into <code>k</code> non-empty subsets whose sums are all equal.</p>

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

<pre>
<strong>Input:</strong> nums = [4,3,2,3,5,2,1], k = 4
<strong>Output:</strong> true
<strong>Explanation:</strong> It is possible to divide it into 4 subsets (5), (1, 4), (2,3), (2,3) with equal sums.
</pre>

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

<pre>
<strong>Input:</strong> nums = [1,2,3,4], k = 3
<strong>Output:</strong> false
</pre>

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

<ul>
	<li><code>1 &lt;= k &lt;= nums.length &lt;= 16</code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>4</sup></code></li>
	<li>The frequency of each element is in the range <code>[1, 4]</code>.</li>
</ul>

class Solution {
public:
    int dp[(1 << 16)][16][16];
    bool fn(int index, int mask, int sum, int kitna, vector<int>& nums, int count, int k) {
        int n = nums.size();
        if (sum == kitna) {
            count++;
            sum = 0;
        }
        if (count > k) return 0;
        if (dp[mask][count][index] != -1) return dp[mask][count][index];
        if (mask == (1 << n) - 1) return count == k;
        bool ans = 0;
        for (int j = 0; j < nums.size(); j++) {
            if ((1 << j)&mask || sum + nums[j] > kitna) continue;
            ans |= fn(j, mask | (1 << j), sum + nums[j], kitna, nums, count, k);
        }
        return dp[mask][count][index] = ans;
    }

    bool canPartitionKSubsets(vector<int>& nums, int k) {
        memset(dp, -1, sizeof(dp));
        int n = nums.size();
        int total = 0;
        for (auto i : nums) total += i;
        if (total % k) return false;
        int kitna = total / k;
        return fn(0, (1 << 0), nums[0], kitna, nums, 0, k);
    }
};
81181