P1082 [NOIP2012 提高组] 同余方程

R45973301

Luogu/problem/P1082/P1082.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int exgcd(int a, int b, int& x, int& y) {
+    if (!b) {
+        x = 1;
+        y = 0;
+        return a;
+    }
+    int d = exgcd(b, a % b, x, y);
+    int t = x;
+    x = y;
+    y = t - (a / b) * y;
+    return d;
+}
+
+int main() {
+    int a, b, x = 0, y = 0;
+    cin >> a >> b;
+    exgcd(a, b, x, y);
+    x = (x % b + b) % b;
+    cout << x << endl;
+    return 0;
+}