打印最长序列

1. A
2. Ctrl+A
3. Ctrl+C
4. Ctrl+V

If you can only press the keyboard for N times (with the above four keys), please write a program to produce maximum numbers of A. If possible, please also print out the sequence of keys.

So the input parameter is N (No. of keys that you can press), the output is M (No. of As that you can produce).

int fun(int n)
{
	int buf[100][4];
	memset(buf, 0, sizeof(buf));

	buf[0][0] = 1;
	for (int i = 1; i < n; i++)
	{
		for (int j = 0; j < 4; j++)
		{
			for (int k = 0; k < 4; k++)
			{
				if (j == 0)//A
				{
					buf[i][j] = max(buf[i][j], buf[i-1][k] + 1);
				}
				else if (j == 1)//CTRL + A
				{
					buf[i][j] = max(buf[i][j], buf[i-1][k]);
				}
				else if (j == 2)//CTRL + C
				{
					if (k == 1)
					{
						buf[i][j] = max(buf[i][j], buf[i-1][k]);
					}
				}
				else//CTRL + V
				{
					if (k == 2)
					{
						buf[i][j] = max(buf[i][j], buf[i-1][k] *2);
					}
				}
			}
		}

	}

	return max(buf[n-1][3], buf[n-1][0]);
}