问题 : Repair the Wall
时间限制: 1 Sec 内存限制: 128 MB题目描述
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.
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
2 2
12 11
14 3
27 11 4
109 5
38 15 6 21 32
5 3
1 1 1
样例输出
1
1
5
impossible
解题思路
水题,直接从大到小往上补就可以了。
#include <stdio.h>
#include <algorithm>
using namespace std;
int main()
{
int l, n, i, s[666];
while (~scanf("%d%d", &l, &n))
{
for (int i = 0; i < n; i++)
scanf("%d", &s[i]);
sort(s, s + n);
for (i = n - 1; i >= 0 && l > 0; i--)
l -= s[i];
if (l > 0)
puts("impossible");
else printf("%d\n", n - i - 1);
}
return 0;
}