Submission #1370921

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Source Code Expand

#include <iostream>
#include<sstream>
#include<vector>
#include<iterator>
#include<numeric>
using namespace std;

typedef unsigned long long ULL;

int main(void)
{
	int N, K;
	cin >> N >> K;

	vector<int> a(N, 0);
	for(int i=0; i<N; i++)
		cin >> a[i];

	double sum;
	ULL k;
	sum = k = accumulate(a.begin(), a.begin()+K, 0);
	for(int right=K, left=0; right<N; right++, left++)
	{
		k += a[right];
		k -= a[left];

		sum += k;
	}

	cout << sum << endl;

	return 0;
}

Submission Info

Judge Result