C :

#include<stdio.h>
int main()
{
	int L, N, sum = 0;
	int A[600] = { 0 };
	while (scanf("%d %d", &L, &N) != EOF)
	{
		for (int i = 0; i < N; i++)
		{
			scanf("%d", &A[i]);
			sum += A[i];
		}
		if (sum < L)
		{
			printf("impossible");

		}
		else
		{
			sum = 0;
			for (int i = 0; i < N; i++)
			{
				for (int j = 0; j < N; j++)
				{
					if (A[i] > A[j])
					{
						A[i] ^= A[j];
						A[j] ^= A[i];
						A[i] ^= A[j];
					}
				}


			}
			int i;
				for (i = 0; i < N; i++)
				{
					if (L>sum)
					{
						sum += A[i];
					}
					else
					{
						break;
					}
				}
				printf("%d\n", i);
				sum = 0;
		}

	}
	return 0;
}

C++ :

#include<stdio.h>
#include<stdlib.h>
#include<algorithm>
int cmp(const void* a,const void* b)  //从大到小
{
    return *(int *)b - *(int *)a;
}
int main()
{
    int L,N,i,j,count,k;
    int ss[700];
    while(scanf("%d%d",&L,&N)!=EOF)
    {
        for(i=0;i<N;i++)
        {
            scanf("%d",&ss[i]);
        }
        qsort(ss,N,sizeof(ss[0]),cmp);
  //      for(i=0;i<N;i++)
    //    printf("%d ",ss[i]);
        count=0;k=0;j=0;
            for(i=0;i<N;i++)
            {
                if(ss[i]+k < L)
                {
                    k+=ss[i];
                    count++;
                }
                else
                {
                    count++;
                    j=1;
                    printf("%d\n",count);
                    break;
                }
            }
            if(j==0)
        printf("impossible\n");
    }
    return 0;
}

Java :

import java.util.Scanner;



class Main {
	
	public static void main(String[] args) {
		Scanner first=new Scanner(System.in);
		while(first.hasNext())
		{
			int L=first.nextInt();
			int N=first.nextInt();
			int[] Ai=new int[N];
			for (int i = 0; i < N; i++) 
			{
				Ai[i]=first.nextInt();
			}
			//Arrays.sort(Ai);
			for (int i = 0; i < Ai.length-1; i++) 
			{
				for (int j = i+1; j < Ai.length; j++) 
				{
					if(Ai[i]<Ai[j])
					{
						int s=Ai[i];
						Ai[i]=Ai[j];
						Ai[j]=s;
					}
				}
			}
			int AiSum=0;
			int count=0;
			boolean flag=true;
			/*for(int i=N-1;i>=0;i--)
			{
				AiSum+=Ai[i];
				count++;
				if(AiSum>=L)
				{
					System.out.println(count);
					flag=false;
					break;
				}
			}*/
			for (int i = 0; i < Ai.length; i++) 
			{
                if(Ai[i]+AiSum < L)  
                {  
                	AiSum+=Ai[i];  
                    count++;  
                }  
                else  
                {  
                    count++;  
                    System.out.println(count); 
                    flag=false;
                    break;  
                } 
			}
			if(flag)
			{
				System.out.println("impossible");
			}
		}
	}
}