n个数选k个数和为x选平方和最大方案

#include<cstdio>
#include<vector>
using namespace std; 
const int maxn=20;
int n,k,x,maxSumSqu=-1,A[maxn];
vector<int>temp,ans;
void DFS(int index,int nowK,int sum,int sumSqu)
{
    if(nowK==k&&sum==x)
    {
        if(sumSqu>maxSumSqu)
        {
            maxSumSqu=sumSqu;
            ans=temp;
        }
        return;
    }
    if(index==n||nowK>k||sum>x)return;
    temp.push_back(A[index]);
    DFS(index+1,nowK+1,sum+A[index],sumSqu+A[index]*A[index]);
    temp.pop_back();
    DFS(index+1,nowK,sum,sumSqu);
 }
 int main()
 {
     A[0]=2;A[1]=2;A[2]=3;A[3]=4;
     n=4;k=2;x=6;
     DFS(0,0,0,0);
     for(int i=0;i<ans.size();i++)
     printf("%d ",ans[i]);
     printf("\n");
     printf("%d",maxSumSqu); 
 }