简单模拟一下那个过程
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<cmath>
#include<set>
#include<queue>
#include<stack>
#include<map>
#define PI acos(-1.0)
#define in freopen("in.txt", "r", stdin)
#define out freopen("out.txt", "w", stdout)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int maxn = 1e5 + 7, maxd = 1e4 + 7, mod = 1e9 + 7;
const ll INF = 0x7f7f7f7f;
int a[maxn];
int n, m, ans;
ll sum;
int main() {
int T;
scanf("%d", &T);
for(int ks = 1; ks <= T; ++ks) {
scanf("%d %d", &n, &m);
sum = 0;
for(int i = 0; i < n; ++i) {
scanf("%d", &a[i]);
sum += a[i];
}
printf("Case #%d: ", ks);
if(sum % (ll)m) { puts("-1"); }
else {
ans = 0;
ll num = 0, t = sum/m;
for(int i = 0; i < n; ++i) {
if(num > 0) ans++;
num += a[i];
while(num > t) {
num -= t;
ans++;
}
if(num == t) num -= t;
}
cout << ans << endl;
}
}
return 0;
}