Equal Sum Arrays With Minimum Number of Operations
<p>You are given two arrays of integers <code>nums1</code> and <code><font face="monospace">nums2</font></code>, possibly of different lengths. The values in the arrays are between <code>1</code> and <code>6</code>, inclusive.</p>

<p>In one operation, you can change any integer&#39;s value in <strong>any </strong>of the arrays to <strong>any</strong> value between <code>1</code> and <code>6</code>, inclusive.</p>

<p>Return <em>the minimum number of operations required to make the sum of values in </em><code>nums1</code><em> equal to the sum of values in </em><code>nums2</code><em>.</em> Return <code>-1</code>​​​​​ if it is not possible to make the sum of the two arrays equal.</p>

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

<pre>
<strong>Input:</strong> nums1 = [1,2,3,4,5,6], nums2 = [1,1,2,2,2,2]
<strong>Output:</strong> 3
<strong>Explanation:</strong> You can make the sums of nums1 and nums2 equal with 3 operations. All indices are 0-indexed.
- Change nums2[0] to 6. nums1 = [1,2,3,4,5,6], nums2 = [<u><strong>6</strong></u>,1,2,2,2,2].
- Change nums1[5] to 1. nums1 = [1,2,3,4,5,<strong><u>1</u></strong>], nums2 = [6,1,2,2,2,2].
- Change nums1[2] to 2. nums1 = [1,2,<strong><u>2</u></strong>,4,5,1], nums2 = [6,1,2,2,2,2].
</pre>

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

<pre>
<strong>Input:</strong> nums1 = [1,1,1,1,1,1,1], nums2 = [6]
<strong>Output:</strong> -1
<strong>Explanation:</strong> There is no way to decrease the sum of nums1 or to increase the sum of nums2 to make them equal.
</pre>

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

<pre>
<strong>Input:</strong> nums1 = [6,6], nums2 = [1]
<strong>Output:</strong> 3
<strong>Explanation:</strong> You can make the sums of nums1 and nums2 equal with 3 operations. All indices are 0-indexed. 
- Change nums1[0] to 2. nums1 = [<strong><u>2</u></strong>,6], nums2 = [1].
- Change nums1[1] to 2. nums1 = [2,<strong><u>2</u></strong>], nums2 = [1].
- Change nums2[0] to 4. nums1 = [2,2], nums2 = [<strong><u>4</u></strong>].
</pre>

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

<ul>
	<li><code>1 &lt;= nums1.length, nums2.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= nums1[i], nums2[i] &lt;= 6</code></li>
</ul>
Greedy; Array; Hash Table; Counting
func minOperations(nums1 []int, nums2 []int) int {
	s1, s2 := sum(nums1), sum(nums2)
	if s1 == s2 {
		return 0
	}
	if s1 > s2 {
		return minOperations(nums2, nums1)
	}
	d := s2 - s1
	arr := []int{}
	for _, v := range nums1 {
		arr = append(arr, 6-v)
	}
	for _, v := range nums2 {
		arr = append(arr, v-1)
	}
	sort.Sort(sort.Reverse(sort.IntSlice(arr)))
	for i, v := range arr {
		d -= v
		if d <= 0 {
			return i + 1
		}
	}
	return -1
}

func sum(nums []int) (s int) {
	for _, v := range nums {
		s += v
	}
	return
}