九度Online Judge

OJ新增积分机制,如有任何问题或者建议,请发帖到九度论坛OJ意见反馈版,祝大家一切顺利!
亲,九度OJ官方微博开通了,欢迎你来粉!微博地址:weibo.com/jobdu

 题目1436-九度Online Judge,用代码记录你的成长之路!

题目1436:Repair the Wall

时间限制:1 秒

内存限制:128 兆

特殊判题:

提交:3274

解决:1448

题目描述:

Long time ago , Kitty lived in a small village. The air was fresh and the scenery was very beautiful. The only thing that troubled her is the typhoon.

When the typhoon came, everything is terrible. It kept blowing and raining for a long time. And what made the situation worse was that all of Kitty's walls were made of wood.

One day, Kitty found that there was a crack in the wall. The shape of the crack is
a rectangle with the size of 1×L (in inch). Luckly Kitty got N blocks and a saw(锯子) from her neighbors.
The shape of the blocks were rectangle too, and the width of all blocks were 1 inch. So, with the help of saw, Kitty could cut down some of the blocks(of course she could use it directly without cutting) and put them in the crack, and the wall may be repaired perfectly, without any gap.

Now, Kitty knew the size of each blocks, and wanted to use as fewer as possible of the blocks to repair the wall, could you help her ?

输入:

The problem contains many test cases, please process to the end of file( EOF ).
Each test case contains two lines.
In the first line, there are two integers L(0<L<1000000000) and N(0<=N<600) which
mentioned above.
In the second line, there are N positive integers. The ith integer Ai(0<Ai<1000000000 ) means that the ith block has the size of 1×Ai (in inch).

输出:

For each test case , print an integer which represents the minimal number of blocks are needed.
If Kitty could not repair the wall, just print "impossible" instead.

样例输入:
5 3
3 2 1
5 2
2 1
样例输出:
2
impossible