求暗黑字符串的个数
import java.util.Scanner;
public class Main {
private static final int MAXN = 35;
private static long dp[] = new long[MAXN];
private static void init() {
dp[1] = 3;
dp[2] = 9;
for (int i = 3; i < MAXN; i++) {
dp[i] = dp[i - 1] * 2 + dp[i - 2];
}
}
public static void main(String[] args) {
Scanner cin = new Scanner(System.in);
init();
while (cin.hasNext()) {
int n = cin.nextInt();
System.out.println(dp[n]);
}
}
}
#网易#
，就是坨屎
