Rearranging Fruits
<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>Choose two indices <code>i</code> and <code>j</code>, and swap the <code>i<sup><font size="1">th</font></sup></code> fruit of <code>basket1</code> with the <code>j<sup><font size="1">th</font></sup></code> 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] &lt;= 10<sup>9</sup></code></li>
</ul>
Greedy; Sort; Array; Hash Table
use std::collections::HashMap;

impl Solution {
    pub fn min_cost(basket1: Vec<i32>, basket2: Vec<i32>) -> i64 {
        let n = basket1.len();
        let mut cnt: HashMap<i32, i32> = HashMap::new();

        for i in 0..n {
            *cnt.entry(basket1[i]).or_insert(0) += 1;
            *cnt.entry(basket2[i]).or_insert(0) -= 1;
        }

        let mut mi = i32::MAX;
        let mut nums = Vec::new();

        for (x, v) in cnt {
            if v % 2 != 0 {
                return -1;
            }
            for _ in 0..(v.abs() / 2) {
                nums.push(x);
            }
            mi = mi.min(x);
        }

        nums.sort();

        let m = nums.len();
        let mut ans = 0;

        for i in 0..(m / 2) {
            ans += nums[i].min(mi * 2) as i64;
        }

        ans
    }
}
