ARC075-E

ARC075-E.cpp

#include <bits/stdc++.h>
using namespace std;

#define fs first
#define se second
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < n; ++i)
#define pb emplace_back

using pii = pair<int, int>;
using vi = vector<int>;
using lint = long long;

const int inf = 1001001001;
const lint linf = 1001001001001001001ll;
const int mod = 1e9 + 7;
const int dx[]{0, 1, 0, -1, -1, -1, 1, 1}, dy[]{1, 0, -1, 0, -1, 1, -1, 1};

template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; } return a > b; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; } return a < b; }
template<typename T> inline void print(const T &x, string s = "\n") { cout << x << s; }
template<typename T> inline void print(const vector<T> &v, string s = " ") 
{ rep(i, v.size()) cout << v[i] << (i + 1 == v.size() ? "\n" : s); }
inline bool inside(int y, int x, int H, int W) { return 0 <= y && y < H && 0 <= x && x < W; }
inline lint in() { lint x; std::cin>>x; return x; }

lint n, k;
vector<lint> a(1, 0), zip;
map<lint, lint> unzip;

lint bit[202020];
lint sum(int i) {
	i++;
	lint s = 0;
	while (i > 0) {
		s += bit[i];
		i -= i & -i;
	}
	return s;
}

void add(int i, int x) {
	i++;
	while (i <= n + 1) {
		bit[i] += x;
		i += i & -i;
	}
}

int main() {
	cin >> n >> k;
	rep(i, n) a.pb(in() - k);

	for (int i = 1; i <= n; ++i) {
		a[i] += a[i - 1];
	}

	for (int i = 0; i <= n; ++i) {
		zip.pb(a[i]);
	}

	sort(all(zip));
	zip.erase(unique(all(zip)), zip.end());
	for (int i = 0; i < zip.size(); ++i) {
		unzip[zip[i]] = i;
	}
	for (int i = 0; i <= n; ++i) {
		a[i] = unzip[a[i]];
	}

	lint ans = 0;
	for (int i = 0; i <= n; ++i) {
		ans += sum(a[i]);
		add(a[i], 1);
	}

	//print(zip);
	//print(a);

	cout << ans << endl;
}