题解 | 小红统计区间（easy）

#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main()
{
    int n, k;
    cin >> n >> k;
    vector<int> arr(n + 1, 0);
    for (int i = 1; i <= n; i++)
    {
        cin >> arr[i];
    }
    int l = 1;
    int sum = 0, ans = 0;
    for (int r = 1; r <= n; r++)
    {
        sum += arr[r];
        if (sum >= k)
        {
            while (sum >= k )
            {
                sum -= arr[l];
                ans += (n - r + 1);
                l++;
            }
        }
        else
        {
            continue;
        }
    }
    cout << ans << endl;
    return 0;
}