求助大佬！！！80分！WA#21、22、23、24、25

#include <iostream>
using namespace std;

long long n, k, s[1000005];

int main () {
	cin >> n >> k; 
	for (int i = 1;i < n; ++i) {
		int x;
		cin >> x;
		s[i] = s[i - 1] + x;
	}
	if (k >= n - 1) {
		cout << 0 <<endl;
		return 0;
	}
	long long ans = s[k];
	for (int i = 2;i <= n - k; ++i) {
		ans = max (ans, s[i + k - 1] - s[i - 1]);
	}
	cout << s[n - 1] - ans <<endl;
	return 0;
}