题解 | #游游的元素修改#

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll>PII;
const int N = 2e5 + 10;
const int MOD = 998244353;
const int INF = 0X3F3F3F3F;
const int dx[] = {-1, 1, 0, 0, -1, -1, +1, +1};
const int dy[] = {0, 0, -1, 1, -1, +1, -1, +1};
const int M = 1e9 + 7;

ll a[N];
int main()
{
	int t;
	cin >> t;
	while(t --){
		int n, l, r;
		cin >> n >> l >> r;
		ll s1 = 0, s2 = 0, s = 0;
		for(int i = 1; i <= n; i ++)
		{
			cin >> a[i];
			s += a[i];
			if(a[i] < l) s1 += l - a[i];
			if(a[i] > r) s2 += a[i] - r;
		}
		if((s / n == r && s % n == 0) || (s / n >= l && s / n < r)) cout << max(s1, s2) << endl;
		else cout << -1 << endl;
	}
	return 0;
}