From f05c95b8e344bb52b035908156eb2a96cc8646cf Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Thu, 13 Oct 2022 19:48:48 +0800
Subject: [PATCH] =?UTF-8?q?P4777=20=E3=80=90=E6=A8=A1=E6=9D=BF=E3=80=91?=
 =?UTF-8?q?=E6=89=A9=E5=B1=95=E4=B8=AD=E5=9B=BD=E5=89=A9=E4=BD=99=E5=AE=9A?=
 =?UTF-8?q?=E7=90=86=EF=BC=88EXCRT=EF=BC=89?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

https://www.luogu.com.cn/record/89726444
---
 Luogu/P4777/P4777.cpp         | 64 +++++++++++++++++++++++++++++++++++
 Luogu/P4777/data/P4777_15.in  |  3 ++
 Luogu/P4777/data/P4777_15.out |  3 ++
 3 files changed, 70 insertions(+)
 create mode 100644 Luogu/P4777/P4777.cpp
 create mode 100644 Luogu/P4777/data/P4777_15.in
 create mode 100644 Luogu/P4777/data/P4777_15.out

diff --git a/Luogu/P4777/P4777.cpp b/Luogu/P4777/P4777.cpp
new file mode 100644
index 00000000..53f3db17
--- /dev/null
+++ b/Luogu/P4777/P4777.cpp
@@ -0,0 +1,64 @@
+#include <iostream>
+#include <algorithm>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n;
+long long a1, b1, a2, b2;
+
+long long exgcd(long long a, long long b, long long& x, long long& y) {
+    if (!b) {
+        x = 1;
+        y = 0;
+        return a;
+    }
+
+    long long g = exgcd(b, a % b, y, x);
+    y -= a / b * x;
+    return g;
+}
+
+long long lcm(long long a, long long b) {
+    return a / std::__gcd(a, b) * b;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        // $x \equiv a_i (mod b_i)$
+        cin >> a2 >> b2;
+
+        if (i == 1) {
+            a1 = a2;
+            b1 = b2;
+        } else {
+            long long x, y,
+                g = exgcd(a1, a2, x, y),
+                c = b2 - b1,
+                m1 = a2 / g,
+                m2 = lcm(a1, a2);
+
+            if (c % g) {
+                cout << -1 << endl;
+
+                exit(0);
+            }
+
+            x = (static_cast<__int128>(x) * c / g % m1 + m1) % m1;
+            b1 = ((a1 * x + b1) % m2 + m2) % m2;
+            a1 = m2;
+        }
+    }
+
+    cout << b1 % a1 << endl;
+
+    return 0;
+}
diff --git a/Luogu/P4777/data/P4777_15.in b/Luogu/P4777/data/P4777_15.in
new file mode 100644
index 00000000..f7dbe092
--- /dev/null
+++ b/Luogu/P4777/data/P4777_15.in
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b28d9bac7d5959c92c3fdc68fec293d5f5b78acd2efb795a12ca977d4bc6c88e
+size 1550359
diff --git a/Luogu/P4777/data/P4777_15.out b/Luogu/P4777/data/P4777_15.out
new file mode 100644
index 00000000..37478da7
--- /dev/null
+++ b/Luogu/P4777/data/P4777_15.out
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:8b0cc1ae37e9818c213ed2ce318563e325f355f3658281638aa271ba02bcda74
+size 14