From 23271050c21cd7a00a9f5ed3d2d2f7d84bd8a248 Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Mon, 23 May 2022 21:25:41 +0800
Subject: [PATCH] =?UTF-8?q?P5596=20=E3=80=90XR-4=E3=80=91=E9=A2=98?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

https://www.luogu.com.cn/record/76300560
---
 Luogu/P5596/P5596.cpp | 61 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 Luogu/P5596/P5596.cpp

diff --git a/Luogu/P5596/P5596.cpp b/Luogu/P5596/P5596.cpp
new file mode 100644
index 00000000..1d5903d3
--- /dev/null
+++ b/Luogu/P5596/P5596.cpp
@@ -0,0 +1,61 @@
+#include <cmath>
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+long long a, b, d, m, ans;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> a >> b;
+
+    d = a * a - b * 4;
+
+    if (d == 0) {
+        cout << "inf" << endl;
+
+        exit(0);
+    } else if (d < 0) {
+        d *= -1;
+        m = std::sqrt(d);
+
+        for (long long q = 1; q <= m; q++) {
+            if (d % q == 0) {
+                long long p = d / q;
+
+                long long x = p - q - 2 * a,
+                          y = p + q;
+
+                if (x % 4 || y % 4) continue;
+
+                x /= 4, y /= 4;
+
+                if (x >= 0 && y >= x) ans++;
+            }
+        }
+    } else {  // d > 0
+        m = std::sqrt(d);
+
+        for (long long q = 1; q <= m; q++) {
+            if (d % q == 0) {
+                long long p = d / q;
+
+                long long x = p + q - 2 * a,
+                          y = p - q;
+
+                if (x % 4 || y % 4) continue;
+
+                x /= 4, y /= 4;
+
+                if (x >= 0 && y >= x) ans++;
+            }
+        }
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}