add 2026-kaist-run-spring

storage/contest/cpp/2026-kaist-run-spring-2.cpp

@@ -0,0 +1,36 @@
+#include <algorithm>
+#include <iostream>
+#include <vector>
+
+#define let auto
+#define fn auto
+#define usize size_t
+using namespace std;
+
+fn fastio() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+}
+
+fn main() -> int {
+    fastio();
+    usize r, u, n;
+    cin >> r >> u >> n;
+
+    usize cnt = r * u;
+    if (n <= 10) {
+        usize fibn = 2;
+        usize fibns1 = 1;
+        usize fibns2 = 1;
+
+        for (usize i = 3; i < n; i++) {
+            fibns2 = fibns1;
+            fibns1 = fibn;
+            fibn = fibns2 + fibns1;
+        }
+        usize delta = ((u - 1) * fibns1 + (r - 1) * fibns2);
+        cout << delta / fibns1 + delta / fibns2 - (delta / (fibns1 * fibns2)) + 1 << endl;
+    } else {
+        cout << cnt << endl;
+    }
+}