<p>You have two fruit baskets containing <code>n</code> fruits each. You are given two <strong>0-indexed</strong> integer arrays <code>basket1</code> and <code>basket2</code> representing the cost of fruit in each basket. You want to make both baskets <strong>equal</strong>. To do so, you can use the following operation as many times as you want:</p>

<ul>
	<li>Chose two indices <code>i</code> and <code>j</code>, and swap the <code>i<font size="1">th</font>&nbsp;</code>fruit of <code>basket1</code> with the <code>j<font size="1">th</font></code>&nbsp;fruit of <code>basket2</code>.</li>
	<li>The cost of the swap is <code>min(basket1[i],basket2[j])</code>.</li>
</ul>

<p>Two baskets are considered equal if sorting them according to the fruit cost makes them exactly the same baskets.</p>

<p>Return <em>the minimum cost to make both the baskets equal or </em><code>-1</code><em> if impossible.</em></p>

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

<pre>
<strong>Input:</strong> basket1 = [4,2,2,2], basket2 = [1,4,1,2]
<strong>Output:</strong> 1
<strong>Explanation:</strong> Swap index 1 of basket1 with index 0 of basket2, which has cost 1. Now basket1 = [4,1,2,2] and basket2 = [2,4,1,2]. Rearranging both the arrays makes them equal.
</pre>

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

<pre>
<strong>Input:</strong> basket1 = [2,3,4,1], basket2 = [3,2,5,1]
<strong>Output:</strong> -1
<strong>Explanation:</strong> It can be shown that it is impossible to make both the baskets equal.
</pre>

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

<ul>
	<li><code>basket1.length == basket2.length</code></li>
	<li><code>1 &lt;= basket1.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= basket1[i],basket2[i]&nbsp;&lt;= 10<sup>9</sup></code></li>
</ul>

from collections import Counter
class Solution:

    def minCost(self, b1: List[int], b2: List[int]) -> int:
        xs, cnt1, cnt2 = set(b1), Counter(b1), Counter()
        for x in b2:
            xs.add(x)
            cnt2[x] += 1
        ys, min_x = [], float('inf')
        
        ys1, ys2 = [], []
        for x in xs:
            min_x = min(x, min_x)
            if (cnt1[x] + cnt2[x])%2 != 0:
                return -1
            if cnt1[x] >  cnt2[x]:
                ys1.append(x)
            elif cnt1[x] < cnt2[x]:
                ys2.append(x)
        def diff(x):
            return abs(cnt1[x]-cnt2[x])//2
        res = 0
        list.sort(ys1)
        list.sort(ys2)
        for y in ys1:
            while ys2 and diff(y) >= diff(ys2[-1]):
                y2 = ys2.pop()
                val = diff(y2)
                cnt1[y] -= val
                cnt2[y] += val
                cnt1[y2] += val
                cnt2[y2] -= val
                res += val*min(y, y2, min_x*2)
            val = diff(y)
            if val == 0:
                continue
            y2 = ys2[-1]
            cnt2[y2] -= val
            cnt1[y2] += val
            cnt1[y] -= val
            cnt2[y] += val
            res += val*min(y, y2, min_x*2)
            if diff(ys2[-1]) == 0:
                ys2.pop()
        return res
        '''
        count = Counter(b1 + b2)
        for c in count:
            if count[c] % 2:
                return -1
            count[c] >>= 1
        A2 = list((Counter(b1) - count).elements())
        B2 = list((Counter(b2) - count).elements())
        small = min(count)
        C = sorted(A2 + B2)
        return sum(min(small * 2, C[i]) for i in range(len(A2)))
        '''
712