分享自认为比较简洁的

#include<iostream>
#include<vector>
using namespace std;
int main()
{
	int n, i, Sum(0), sum(0), count(0);
	cin >> n;
	vector<int>a;
	while (cin >> i)
	{
		Sum += i;
		a.push_back(i);
	}
	for (i = 0; i < n; i++)
		a[i] -= Sum / n;
	for (i = 0; i <n-1; i++)
	{
		if (a[i] + sum != 0)
			count++;
		sum += a[i];
	}
	cout << count;
}
把N堆纸牌分成左右两部分，来计算两堆纸牌间是否要交换。