diff --git "a/Seol-JY/202502/23 BOJ G4 \355\203\200\354\235\274 \354\261\204\354\232\260\352\270\260 3.md" "b/Seol-JY/202502/23 BOJ G4 \355\203\200\354\235\274 \354\261\204\354\232\260\352\270\260 3.md" new file mode 100644 index 00000000..6eba96b5 --- /dev/null +++ "b/Seol-JY/202502/23 BOJ G4 \355\203\200\354\235\274 \354\261\204\354\232\260\352\270\260 3.md" @@ -0,0 +1,24 @@ +```java +import java.io.*; +public class Main { + static int N; + static final int MOD = 1000000007; + static long[][] dp = new long[1000001][2]; + + public static void main(String[] args) throws IOException { + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + N = Integer.parseInt(br.readLine()); + dp[0][0] = 0; + dp[1][0] = 2; + dp[2][0] = 7; + dp[2][1] = 1; + + for (int i = 3; i <= N; i++) { + dp[i][1] = (dp[i - 3][0] + dp[i - 1][1]) % MOD; // i - 3 까지 누적합 + 1 + dp[i][0] = (3 * (dp[i - 2][0]) + 2 * (dp[i - 1][0]) + 2 * dp[i][1]) % MOD; + } + + System.out.println(dp[N][0]); + } +} +```