思路是从大到小变成平均值

#include<bits/stdc++.h>
#define N 202000
#define M 2020
#define ll long long
using namespace std;
ll n, a[N], step, sum;
bool cmp( ll A, ll B ){
	return A > B;
}
bool check(){
	for ( int i = 1; i <= n; i++ ){
		if ( a[i] != sum ){
			return 1;
		}
	}
	return 0;
}
int main(){
	cin.tie(0);cout.tie(0);
	cin >> n;
	for ( int i = 1; i <= n; i++ ){
		cin >> a[i];
		sum += a[i];
	}
	sum /= n;
	while(check()){
		sort ( a + 1, a + n + 1 );
		ll t = sum - a[1];
		a[n] -= t;
		a[1] = sum;
		step++;
	}
	cout << step;
	return 0;
}