'commit'

TangDou/AcWing_TiGao/T5/ZhuHeJiShu/1310.cpp

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define int long long
+#define endl "\n"
+
+// C(n,3)计算公式
+int C(int n) {
+    return n * (n - 1) * (n - 2) / (3 * 2 * 1);
+}
+
+signed main() {
+    int n, m;
+    cin >> n >> m; // 行数,列数
+    n++, m++;      // 将格子数转换成格点数,n->n+1,m->m+1
+
+    int res = C(n * m) - n * C(m) - m * C(n);
+    // 枚举所有高为i,宽为j的线段AB
+    for (int i = 1; i <= n; i++)
+        for (int j = 1; j <= m; j++)
+            res -= 2 * (__gcd(i, j) - 1) * (n - i) * (m - j);
+
+    printf("%lld\n", res);
+}