# 321. Create Maximum Number

Given two arrays of length `m` and `n` with digits `0-9` representing two numbers. Create the maximum number of length `k <= m + n` from digits of the two. The relative order of the digits from the same array must be preserved. Return an array of the `k` digits.

Note: You should try to optimize your time and space complexity.

Example 1:

``````Input:
nums1 = [3, 4, 6, 5]
nums2 = [9, 1, 2, 5, 8, 3]
k = 5
Output:
[9, 8, 6, 5, 3]
``````

Example 2:

``````Input:
nums1 = [6, 7]
nums2 = [6, 0, 4]
k = 5
Output:
[6, 7, 6, 0, 4]
``````

Example 3:

``````Input:
nums1 = [3, 9]
nums2 = [8, 9]
k = 3
Output:
[9, 8, 9]
``````

Credits:
Special thanks to @dietpepsi for adding this problem and creating all test cases.

``````class Solution {
public:
vector<int> maxNumber(vector<int>& nums1, vector<int>& nums2, int k) {
int n1 = nums1.size(), n2 = nums2.size();
vector<int> res;
for (int i = max(0, k - n2); i <= min(k, n1); ++i) {
res = max(res, mergeVector(maxVector(nums1, i), maxVector(nums2, k - i)));
}
return res;
}
vector<int> maxVector(vector<int>& nums, int k) {
int drop = (int)nums.size() - k;
vector<int> res;
for (int num : nums) {
while (drop > 0 && !res.empty() && res.back() < num) {
res.pop_back();
--drop;
}
res.push_back(num);
}
res.resize(k);
return res;
}
vector<int> mergeVector(vector<int> nums1, vector<int> nums2) {
vector<int> res;
while (!nums1.empty() || !nums2.empty()) {
vector<int> &tmp = (nums1 > nums2) ? nums1 : nums2;
res.push_back(tmp[0]);
tmp.erase(tmp.begin());
}
return res;
}
};
``````

Github 同步地址：

https://github.com/grandyang/leetcode/issues/321

Maximum Swap

Remove K Digits

Remove Duplicate Letters

https://leetcode.com/problems/create-maximum-number/

https://leetcode.com/problems/create-maximum-number/discuss/77285/Share-my-greedy-solution

https://leetcode.com/problems/create-maximum-number/discuss/77287/C%2B%2B-16ms-FASTEST-beats-97.

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