Problem:
Score : 600 points

Problem Statement

You are given an integer sequence of length N, a = {a_1, a_2, …, a_N}, and an integer K.

a has N(N+1)/2 non-empty contiguous subsequences, {a_l, a_{l+1}, …, a_r} (1 ≤ l ≤ r ≤ N). Among them, how many have an arithmetic mean that is greater than or equal to K?

Constraints

All input values are integers.

1 ≤ N ≤ 2 \times 10^5

1 ≤ K ≤ 10^9

1 ≤ a_i ≤ 10^9

Input

Input is given from Standard Input in the following format:

N K
a_1
a_2
:
a_N

Output

Print the number of the non-empty contiguous subsequences with an arithmetic mean that is greater than or equal to K.

Sample Input 1

3 6
7
5
7

Sample Output 1

5

All the non-empty contiguous subsequences of a are listed below:

{a_1} = {7}

{a_1, a_2} = {7, 5}

{a_1, a_2, a_3} = {7, 5, 7}

{a_2} = {5}

{a_2, a_3} = {5, 7}

{a_3} = {7}

Their means are 7, 6, 19/3, 5, 6 and 7, respectively, and five among them are 6 or greater. Note that {a_1} and {a_3} are indistinguishable by the values of their elements, but we count them individually.

Sample Input 2

1 2
1

Sample Output 2

0

Sample Input 3

7 26
10
20
30
40
30
20
10

Sample Output 3

13

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;

public class Main {
    //-------------------------------------------------------------//
    public static final void main(String[] args) {
        new Main().solve();
    }
    //-------------------------------------------------------------//
    private final Scanner sc = new Scanner(System.in);

    void solve() {
        int N = sc.nextInt();
        long K = sc.nextInt();
        long[] a = new long[N];
        a[0] = sc.nextLong();
        for (int i = 1; i < N; i++) {
            a[i] = a[i - 1] + sc.nextLong();
        }

        int ans = 0;
        for (int i = 0; i < N; i++) {
            for (int len = 0; len < N - i; len++) {
                if (i == 0) {
                    if (a[i + len] / (len + 1) >= K)
                        ans++;
                }
                else if (a[i + len] - a[i - 1] / (len + 1) >= K) {
                    ans++;
                }
            }
        }
        System.out.println(ans);
    }
}