From 6067adf5c31343d36b25167d7055c831979c7166 Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Mon, 6 Feb 2023 17:22:53 +0800
Subject: [PATCH] =?UTF-8?q?P5505=20[JSOI2011]=E5=88=86=E7=89=B9=E4=BA=A7?=
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https://www.luogu.com.cn/record/101578696
---
 Luogu/P5505/P5505.cpp | 53 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Luogu/P5505/P5505.cpp

diff --git a/Luogu/P5505/P5505.cpp b/Luogu/P5505/P5505.cpp
new file mode 100644
index 00000000..c448136a
--- /dev/null
+++ b/Luogu/P5505/P5505.cpp
@@ -0,0 +1,53 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2005;
+const int mod = 1e9 + 7;
+
+int n, m, a[N], c[N][N], f[N], ans;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    c[0][0] = 1;
+
+    for (int i = 1; i < N; ++i) {
+        c[i][0] = 1;
+
+        for (int j = 1; j <= i; ++j) {
+            c[i][j] = (static_cast<long long>(c[i - 1][j - 1]) + c[i - 1][j]) % mod;
+        }
+    }
+
+    cin >> n >> m;
+
+    for (int i = 1; i <= m; i++) {
+        cin >> a[i];
+    }
+
+    for (int i = 0; i < n; i++) {
+        f[i] = 1;
+
+        for (int j = 1; j <= m; j++) {
+            f[i] = static_cast<long long>(f[i]) * c[n - i + a[j] - 1][n - i - 1] % mod;
+        }
+
+        f[i] = static_cast<long long>(f[i]) * c[n][i] % mod;
+    }
+
+    for (int i = 0; i < n; i++) {
+        if (i % 2 == 0) {
+            ans = (static_cast<long long>(ans) + f[i]) % mod;
+        } else {
+            ans = (static_cast<long long>(ans) - f[i] + mod) % mod;
+        }
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}