Add 12849.cpp

12xxx/12849.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+#include <vector>
+#define MOD 1000000007
+using namespace std;
+
+void solve(void) {
+  int d; cin >> d;
+
+  vector<vector<long long>> dp(d+1, vector<long long>(8, 0));
+  dp[0][0] = 1;
+  for (int i=1; i<=d; i++) {
+    dp[i][0] = (dp[i-1][1] + dp[i-1][2]) % MOD;
+    dp[i][1] = (dp[i-1][0] + dp[i-1][2] + dp[i-1][3]) % MOD;
+    dp[i][2] = (dp[i-1][0] + dp[i-1][1] + dp[i-1][3] + dp[i-1][4]) % MOD;
+    dp[i][3] = (dp[i-1][1] + dp[i-1][2] + dp[i-1][4] + dp[i-1][5]) % MOD;
+    dp[i][4] = (dp[i-1][2] + dp[i-1][3] + dp[i-1][5] + dp[i-1][6]) % MOD;
+    dp[i][5] = (dp[i-1][3] + dp[i-1][4] + dp[i-1][7]) % MOD;
+    dp[i][6] = (dp[i-1][4] + dp[i-1][7]) % MOD;
+    dp[i][7] = (dp[i-1][5] + dp[i-1][6]) % MOD;
+  }
+
+  cout << dp[d][0];
+}
+
+int main(void) {
+  ios::sync_with_stdio(false);
+  cin.tie(nullptr); cout.tie(nullptr);
+
+  solve();
+  return 0;
+}