<p>You are given an integer array <code>nums</code>. In one move, you can pick an index <code>i</code> where <code>0 &lt;= i &lt; nums.length</code> and increment <code>nums[i]</code> by <code>1</code>.</p>

<p>Return <em>the minimum number of moves to make every value in </em><code>nums</code><em> <strong>unique</strong></em>.</p>

<p>The test cases are generated so that the answer fits in a 32-bit integer.</p>

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

<pre>
<strong>Input:</strong> nums = [1,2,2]
<strong>Output:</strong> 1
<strong>Explanation:</strong> After 1 move, the array could be [1, 2, 3].
</pre>

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

<pre>
<strong>Input:</strong> nums = [3,2,1,2,1,7]
<strong>Output:</strong> 6
<strong>Explanation:</strong> After 6 moves, the array could be [3, 4, 1, 2, 5, 7].
It can be shown that it is impossible for the array to have all unique values with 5 or less moves.
</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>0 &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
</ul>


#include <map>
#include <vector>
#include <algorithm>



class Solution {
public:
    int minIncrementForUnique(std::vector<int>& nums) {
		int count = 0;
		int result = 0;
		std::map<int, int> map;

		for (int num : nums)
			++map[num];

		for (auto curr = map.begin(), next = std::next(curr); curr != map.end(); ++curr, ++next) {
			if (curr->second == 1)
				continue;

			if (next != map.end()) {
				count = std::min(curr->second - 1, next->first - curr->first - 1);
				result += (count + 1) * count / 2 + (curr->second - 1 - count) * (next->first - curr->first);
				next->second += curr->second - 1 - count;
			} else {
				result += curr->second * (curr->second - 1) / 2;
			}
		}

		return result;
    }
};
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