题解 | 牛牛与切割机

#include <bits/stdc++.h>
using namespace std;
long long arr[2000086];
long long sum[2000086];
int main()
{
    long long n;
    cin >> n;
    for (long long i = 1; i <= n; i++)
    {
        cin >> arr[i];
        sum[i] = sum[i - 1] + arr[i];
    }
    long long min = 1e18;
    for (long long i = 1; i < n; i++)
    {
        long long temp1 = sum[n] - sum[i];
        long long temp2 = sum[i];
        long long temp = temp1 * temp2;
        if (temp < min)
            min = temp;
    }
    cout << min;
    return 0;
}