From 144492f9d439ed59fa8955fdcc7a72480c8bf2a5 Mon Sep 17 00:00:00 2001
From: Ren Baoshuo <i@baoshuo.ren>
Date: Sun, 3 Jan 2021 21:38:43 +0800
Subject: [PATCH] =?UTF-8?q?P1990=20=E8=A6=86=E7=9B=96=E5=A2=99=E5=A3=81?=
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R44593612
---
 Luogu/problem/P1990/P1990.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 Luogu/problem/P1990/P1990.cpp

diff --git a/Luogu/problem/P1990/P1990.cpp b/Luogu/problem/P1990/P1990.cpp
new file mode 100644
index 00000000..03af7d28
--- /dev/null
+++ b/Luogu/problem/P1990/P1990.cpp
@@ -0,0 +1,15 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, dp[1000009];
+
+int main() {
+    dp[1] = 1, dp[2] = 2, dp[3] = 5;
+    cin >> n;
+    for (int i = 4; i <= n; i++) {
+        dp[i] = (dp[i - 1] * 2 + dp[i - 3]) % 10000;
+    }
+    cout << dp[n] << endl;
+    return 0;
+}
\ No newline at end of file