'commit'

TangDou/LanQiaoBei/LanQiao14GuoSai/Test.cpp

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+const int MOD = 1000000007;
+typedef long long LL;
+/*
+3 5 4
+
+36
+*/
+int main() {
+    LL n, m, k;
+    cin >> n >> m >> k;
+    // k=4 m=5
+    LL a = ((k - 1) * (m - k + 1)) % MOD;
+
+    // LL b = 0;
+    // for (LL i = 1; i <= n; i++) b = (b + i) % MOD;
+    LL b = (n * (n + 1) / 2) % MOD;
+
+    cout << (a * b) % MOD << endl;
+    return 0;
+}