Language: C++

//#include "IntMod.h"
//typedef IntMod<1000000007> MInt;

//#include "Union_Find.h"

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <string>
#include <vector>
#include <utility>
#include <algorithm>
#include <functional>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <iomanip>
#include <sstream>
#include <numeric>
#include <list>
#include <bitset>

using namespace std;
#define REP(i,a,n) for(int i = (a); i < (int)(n); ++i)
#define REPM(i,n,a) for(int i = ((n) - 1); i >= (a); --i)
#define EPS 0.0001
#define INF 0x3FFFFFFF
#define INFLL 0x3FFFFFFF3FFFFFFF
#define INFD 1.0e+308
#define FLOAT setprecision(16)
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<LL, LL> PP;

template <class T, class U>
istream& operator>>(istream& ist, pair<T, U>& right) { return ist >> right.first >> right.second; }
template <class T, class U>
ostream& operator<<(ostream& ost, pair<T, U>& right) { return ost << right.first << ' ' << right.second; }
template <class T, class TCompatible, size_t N>
void Fill(T(&dest)[N], const TCompatible& val) { fill(begin(dest), end(dest), val); }
template <class T, class TCompatible, size_t M, size_t N>
void Fill(T(&dest)[M][N], const TCompatible& val) { for (int i = 0; i < M; ++i) Fill(dest[i], val); }
//sum, 累積和
// 負のときの割り算に注意
#if 1
#include <array>
#include <unordered_set>
#include <unordered_map>
template<class T>
using PriorityQ = priority_queue<T, vector<T>, greater<T> >;	// コスト小を優先
#endif



template <typename T>
class SegmentTree {
	using FuncType = std::function<T(const T&, const T&)>;

private:
	T* val_p_m;
	const T init_val_m;
	const int size_m;
	const int rank_m;

	const FuncType func_m;

	T Query_rec(int range_left, int range_right, int node_index, int node_range_left, int node_range_right);
	bool Is_valid_index(int index);
public:
	SegmentTree(int size, const T& init_val, const FuncType& func);

	void Update(int pos, const T& val);
	T Query(int range_left, int range_right);
};

template<typename T>
T SegmentTree<T>::Query_rec(int range_left, int range_right, int node_index, int node_range_left, int node_range_right) {
	if (node_range_right <= range_left || range_right <= node_range_left) return init_val_m;
	if (range_left <= node_range_left && node_range_right <= range_right) return val_p_m[node_index];

	int node_range_mid = (node_range_left + node_range_right) / 2;
	const T val_left = Query_rec(range_left, range_right, node_index * 2, node_range_left, node_range_mid);
	const T val_right = Query_rec(range_left, range_right, node_index * 2 + 1, node_range_mid, node_range_right);
	return func_m(val_left, val_right);
}

template<typename T>
inline bool SegmentTree<T>::Is_valid_index(int index) {
	return index >= 0 && index < size_m;
}

template<typename T>
SegmentTree<T>::SegmentTree(int size, const T& init_val, const FuncType& func)
	: init_val_m(init_val), size_m(size), rank_m((int)std::log2(size) + 1), func_m(func) {

	val_p_m = new T[1 << rank_m];
	fill(val_p_m + (1 << (rank_m - 1)), val_p_m + (1 << rank_m), init_val_m);

	for (int i = (1 << (rank_m - 1)) - 1; i >= 1; --i) {
		val_p_m[i] = func_m(val_p_m[i * 2], val_p_m[i * 2 + 1]);
	}
}

template<typename T>
void SegmentTree<T>::Update(int pos, const T& val) {
	assert(Is_valid_index(pos));

	int i = pos + (1 << (rank_m - 1));
	val_p_m[i] = val;
	while (i > 1) {
		i /= 2;
		val_p_m[i] = func_m(val_p_m[i * 2], val_p_m[i * 2 + 1]);
	}
}

template<typename T>
T SegmentTree<T>::Query(int range_left, int range_right) {
	assert(Is_valid_index(range_left));
	assert(Is_valid_index(range_right - 1));

	return Query_rec(range_left, range_right, 1, 0, 1 << (rank_m - 1));
}

template<typename T>
class Max {
public:
	const T& operator()(const T& a, const T& b) const {
		return max<T>(a, b);
	}
};

template<typename T>
class Min {
public:
	const T& operator()(const T& a, const T& b) const {
		return min<T>(a, b);
	}
};

LL N, F;
LL A[100000];
LL B[100001];
map<LL, vector<int> > M;
vector<PP> C;
int main() {
	cin >> N >> F;

	REP(i, 0, N) {
		cin >> A[i];
	}
	B[0] = 0;
	REP(i, 1, N + 1) {
		B[i] = B[i - 1] + A[i - 1] - F;
	}
	REP(i, 0, N + 1) {
		M[B[i]].push_back(i);
	}
	int c = 0;
	for (auto&& p : M) {
		for (int i : p.second) {
			C.push_back(PP(i, c));
		}
		++c;
	}
	sort(C.begin(), C.end());

	LL ans = 0;
	SegmentTree<int> S(N + 1, 0, plus<int>());
	REP(i, 0, N + 1) {
		ans += S.Query(0, C[i].second + 1);
		S.Update(C[i].second, S.Query(C[i].second, C[i].second + 1) + 1);
	}
	cout << ans << endl;
	return 0;
}

Compiler output:
a.cc: In instantiation of 'T SegmentTree<T>::Query(int, int) [with T = int]':
a.cc:173:17:   required from here
  173 |                 ans += S.Query(0, C[i].second + 1);
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~
a.cc:121:15: error: 'assert' was not declared in this scope
  121 |         assert(Is_valid_index(range_left));
      |         ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:51:1: note: 'assert' is defined in header '<cassert>'; this is probably fixable by adding '#include <cassert>'
   50 | #include <unordered_set>
  +++ |+#include <cassert>
   51 | #include <unordered_map>
a.cc:122:15: error: 'assert' was not declared in this scope, and no declarations were found by argument-dependent lookup at the point of instantiation
  122 |         assert(Is_valid_index(range_right - 1));
      |         ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:121:15: note: 'assert' declared here, later in the translation unit
  121 |         assert(Is_valid_index(range_left));
      |         ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc: In instantiation of 'void SegmentTree<T>::Update(int, const T&) [with T = int]':
a.cc:174:11:   required from here
  174 |                 S.Update(C[i].second, S.Query(C[i].second, C[i].second + 1) + 1);
      |                 ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:109:15: error: 'assert' was not declared in this scope
  109 |         assert(Is_valid_index(pos));
      |         ~~~~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:109:15: note: 'assert' is defined in header '<cassert>'; this is probably fixable by adding '#include <cassert>'