4268. 性感素数

https://www.acwing.com/problem/content/submission/code_detail/14678536/

AcWing/4268/4268.cpp

@@ -0,0 +1,42 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+bool isPrime(int x) {
+    if (x <= 1) return false;
+
+    for (int i = 2; i * i <= x; i++) {
+        if (x % i == 0) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int x;
+
+    cin >> x;
+
+    if (isPrime(x) && isPrime(x - 6)) {
+        cout << "Yes" << endl
+             << x - 6 << endl;
+    } else if (isPrime(x) && isPrime(x + 6)) {
+        cout << "Yes" << endl
+             << x + 6 << endl;
+    } else {
+        cout << "No" << endl;
+
+        while (!(isPrime(x) && (isPrime(x - 6) || isPrime(x + 6)))) x++;
+
+        cout << x << endl;
+    }
+
+    return 0;
+}