GYM 101673G（dp）

dp[i][j][0/1]：第i天处于第j状态要不要吃。

const int maxn = 1e2 + 5;
int n, a[maxn], b[maxn];
int dp[maxn][maxn][2];

int main() {
	read(n), read(b[1]);
	rep(i, 1, n)	read(a[i]);
	rep(i, 2, n)	b[i] = b[i - 1] * 2 / 3;

	rep(i, 1, n) {
		rep(j, 1, i) {
			dp[i][j][0] = dp[i - 1][j + 1][0];
			dp[i][j][1] = dp[i - 1][j + 1][0] + min(a[i], b[j]);
			if (j >= 2) {
				dp[i][j][0] = max(dp[i][j][0], dp[i - 1][j - 1][1]);
				dp[i][j][1] = max(dp[i][j][1], dp[i - 1][j - 1][1] + min(a[i], b[j]));
			}
			if (i > 3)	{
				dp[i][1][0] = max(dp[i][1][0], max(dp[i - 3][j][0], dp[i - 3][j][1]));
				dp[i][1][1] = max(dp[i][1][1], dp[i][1][0] + min(a[i], b[1]));
			}
			
		}
	}

	int ans = 0;
	rep(i, 1, n) {
		ans = max(max(dp[n][i][0], dp[n][i][1]), ans);
	}
	writeln(ans);
	return 0;
}