#480. 造题

https://sjzezoj.com/submission/14145

S2OJ/480/480.cpp

@@ -0,0 +1,40 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+long long n, m, t, ans, x;
+
+long long gcd(long long a, long long b) {
+    if (!b) return a;
+    return gcd(b, a % b);
+}
+
+int main() {
+    cin >> n >> m >> t;
+    if (!m) {
+        cout << -1 << endl;
+        exit(0);
+    }
+    if (!n) {
+        cout << 0 << endl;
+        exit(0);
+    }
+    x = gcd(n, m);
+    n /= x;
+    m /= x;
+    while (n != 1 || m != 1) {
+        if (n < m) swap(n, m);
+        ans += n / m;
+        n %= m;
+        if (!n) {
+            n += m;
+            ans--;
+        }
+        if (n < 1 || m < 1) {
+            cout << -1 << endl;
+            exit(0);
+        }
+    }
+    cout << ++ans * t << endl;
+    return 0;
+}