只能买3个物品 尽可能花光钱

#include<bits/stdc++.h>
using namespace std;
int num, sum,sum1=0,count1 =0, r;
int a[100];
vector<int>vec;

int main() {
    for (int i = 0; i < 100; i++) {      
        cin >> a[i];
      //  cout << "a[i]" << a[i] << endl;
        count1++;
        if (cin.get() == '\n') break;
    }
   //   cout <<"count1" << count1 << endl;
    cin >> r;

    for (int i = 0; i < count1 - 2; i++) {
      
        for (int j = i+1; j < count1 - 1; j++) {
      
            for (int k = j+1; k < count1; k++) {
                sum = a[i] + a[j] + a[k];
                cout << "i" << i << "j" << j << "k" << k << endl;
                cout << sum << endl;
                vec.push_back(sum);
            }
        }
    }
    vector<int>::iterator i;
    for (i = vec.begin(); i < vec.end(); i++) {
       // cout << *i<< endl;
       // if (*i > r) cout << *i<<">"<<r << endl;
        if (sum1 < *i&&*i<=r) {
                sum1 = *i;
            
         }
            
        
    }
    cout << sum1 << endl;
    return 0;
}