From 0f4f1a4fb9add9f735bf4e91be4866e4f1350a2d Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Thu, 26 May 2022 09:29:22 +0800
Subject: [PATCH] =?UTF-8?q?P2717=20=E5=AF=92=E5=81=87=E4=BD=9C=E4=B8=9A?=
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https://www.luogu.com.cn/record/76400157
---
 Luogu/P2717/P2717.cpp | 56 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 Luogu/P2717/P2717.cpp

diff --git a/Luogu/P2717/P2717.cpp b/Luogu/P2717/P2717.cpp
new file mode 100644
index 00000000..cc21ef7b
--- /dev/null
+++ b/Luogu/P2717/P2717.cpp
@@ -0,0 +1,56 @@
+#include <algorithm>
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, k, a[N], b[N];
+long long ans;
+
+void solve(int l, int r) {
+    if (l == r) {
+        if (a[l] >= 0) ans++;
+        return;
+    }
+
+    int mid = l + r >> 1;
+
+    solve(l, mid);
+    solve(mid + 1, r);
+
+    b[mid] = a[mid];
+    for (int i = mid - 1; i >= l; i--) b[i] = b[i + 1] + a[i];
+    std::sort(b + l, b + mid + 1);
+
+    b[mid + 1] = a[mid + 1];
+    for (int i = mid + 2; i <= r; i++) b[i] = b[i - 1] + a[i];
+    std::sort(b + mid + 1, b + r + 1);
+
+    int i = l, j = r;
+    while (i <= mid) {
+        while (j > mid && b[i] + b[j] >= 0) j--;
+        ans += r - j;
+        i++;
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n >> k;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+
+        a[i] -= k;
+    }
+
+    solve(1, n);
+
+    cout << ans << endl;
+
+    return 0;
+}