#1732. 【NOIP 2022 模拟赛 by AzusaCat】小黄鸭与矩阵（matrix）

https://sjzezoj.com/submission/63545

S2OJ/1732/1732.cpp

@@ -0,0 +1,28 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int n, k;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> k;
+
+    int a = n / k,
+        b = (n - 1) / k + 1;
+    int cb = n % k,
+        ca = k - n % k;
+    long long res = 0;
+
+    res += static_cast<long long>(ca) * (ca - 1) / 2 * a * a;
+    res += static_cast<long long>(cb) * (cb - 1) / 2 * b * b;
+    res += static_cast<long long>(a) * b * ca * cb;
+
+    cout << res << endl;
+
+    return 0;
+}