POJ1564 ——Sum It Up

#include <stdio.h>
#include <string.h>
int ans,n,a[1001];
int b[1010];
bool f;
void dfs(int v,int t,int g)
{
int i;
if(v==ans)
{
f = true;
for(i=1;i<t-1;i++)
printf("%d+",b[i]);
printf("%d\n",b[t-1]);
return;
}
for(i=g;i>=0;i--)
{
if(a[i])
{
if(i+v > ans) continue;
else
{
a[i]--;
b[t] = i;
dfs(i+v,t+1,i);
a[i]++;
}
}
}
}
int main(void)
{
int i,data;
int maxx;
while(scanf("%d %d",&ans,&n)!=EOF && (ans!=0 || n!=0))
{
memset(a,0,sizeof(a));
maxx = -1;
for(i=1;i<=n;i++)
{
scanf("%d",&data);
if(data > maxx) maxx = data;
a[data]++;
}
f = false;
printf("Sums of %d:\n",ans);
dfs(0,1,maxx);
if(!f)
printf("NONE\n");
}
return 0;
}