<p>You are given two integer arrays <code>nums1</code> and <code>nums2</code> of lengths <code>m</code> and <code>n</code> respectively. <code>nums1</code> and <code>nums2</code> represent the digits of two numbers. You are also given an integer <code>k</code>.</p>

<p>Create the maximum number of length <code>k &lt;= m + n</code> from digits of the two numbers. The relative order of the digits from the same array must be preserved.</p>

<p>Return an array of the <code>k</code> digits representing the answer.</p>

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

<pre>
<strong>Input:</strong> nums1 = [3,4,6,5], nums2 = [9,1,2,5,8,3], k = 5
<strong>Output:</strong> [9,8,6,5,3]
</pre>

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

<pre>
<strong>Input:</strong> nums1 = [6,7], nums2 = [6,0,4], k = 5
<strong>Output:</strong> [6,7,6,0,4]
</pre>

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

<pre>
<strong>Input:</strong> nums1 = [3,9], nums2 = [8,9], k = 3
<strong>Output:</strong> [9,8,9]
</pre>

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

<ul>
	<li><code>m == nums1.length</code></li>
	<li><code>n == nums2.length</code></li>
	<li><code>1 &lt;= m, n &lt;= 500</code></li>
	<li><code>0 &lt;= nums1[i], nums2[i] &lt;= 9</code></li>
	<li><code>1 &lt;= k &lt;= m + n</code></li>
</ul>

class Solution {
public:
    vector<int> maxNumber(vector<int>& nums1, vector<int>& nums2, int k) {
        vector<int> ord1(nums1.size());
        vector<pair<int, int>> stk;
        int cur = nums1.size();
        for (int i = 0; i < nums1.size(); i++)
        {
            while (!stk.empty() && stk.back().first < nums1[i])
            {
                ord1[stk.back().second] = cur--;
                stk.pop_back();
            }
            stk.push_back(make_pair(nums1[i], i));
        }
        while (!stk.empty())
        {
            ord1[stk.back().second] = cur--;
            stk.pop_back();
        }

        vector<int> ord2(nums2.size());
        cur = nums2.size();
        for (int i = 0; i < nums2.size(); i++)
        {
            while (!stk.empty() && stk.back().first < nums2[i])
            {
                ord2[stk.back().second] = cur--;
                stk.pop_back();
            }
            stk.push_back(make_pair(nums2[i], i));
        }
        while (!stk.empty())
        {
            ord2[stk.back().second] = cur--;
            stk.pop_back();
        }

        vector<int> ret;
        for (int i = max(0, k - (int)nums2.size()); i <= min(k, (int)nums1.size()); i++)
        {
            int len1 = i, len2 = k - i;
            list<int> v1, v2;
            for (int j = 0; j < nums1.size(); j++)
                if (ord1[j] <= i)
                    v1.push_back(nums1[j]);
            for (int j = 0; j < nums2.size(); j++)
                if (ord2[j] <= k - i)
                    v2.push_back(nums2[j]);
            vector<int> now;
            while (!v1.empty() && !v2.empty())
                if (v1 > v2)
                    now.push_back(v1.front()), v1.pop_front();
                else
                    now.push_back(v2.front()), v2.pop_front();
            while (!v1.empty())
                now.push_back(v1.front()), v1.pop_front();
            while (!v2.empty())
                now.push_back(v2.front()), v2.pop_front();
            if (now > ret)
                ret = now;
        }
        return ret;
    }
};
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