hdu1258 dfs 给一个指定的target数和一个数列，要求不重复选择其中的数使得和为target并打印，结果不可重复。

#include<bits/stdc++.h>
using namespace std;
typedef unsigned int ui;
typedef long long ll;
typedef unsigned long long ull;
#define pf printf
#define prime1 1e9+7
#define prime2 1e9+9
#define scand(x) scanf("%llf",&x)
#define f(i,a,b) for(int i=a;i<=b;i++)
#define scan(a) scanf("%d",&a)
#define dbg(args) cout<<#args<<":"<<args<<endl;
#define pb(i) push_back(i)
#define ppb(x) pop_back(x)
#define maxn 100
int n,m,t,cnt;
int a[maxn],b[maxn];
void dfs(int sum,int posa,int posb)
{
    if(sum>m)return;
    if(sum==m)
    {
        cnt++;
        f(i,1,posb-1)
        {
            if(i!=1)
            {
                pf("+%d",b[i]);
            }
            else pf("%d",b[1]);
        }
        pf("
");
        return;
    }
    f(i,posa,n)
    {
        b[posb]=a[i];
        dfs(sum+b[posb],i+1,posb+1);
        while(i+1<=n&&a[i]==a[i+1])i++;
    }
    return ;
}
int main()
{
    std::ios::sync_with_stdio(false);
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    while(scanf("%d %d",&m,&n)==2&&!(n==0&&m==0))
    {
        cnt=0;
        memset(a,0,sizeof(a));
        memset(b,0,sizeof(b));
        f(i,1,n)scan(a[i]);
        sort(a+1,a+n+1,greater<int>());
        pf("Sums of %d:
",m);
        dfs(0,1,1);
        if(!cnt)
        {
            pf("NONE
");
        }
    }
 }