Optimize and speed up processing of code to <=1sec (per test case)

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

class gfg
{
public:
bool satisfiable(std::vector<int> a, std::vector<int> b) {
  while (!a.empty()) {
    std::sort(b.begin(), b.end(), std::greater<int>());
    int k = a.back();
    a.pop_back();
    if (k > b.size()) return false;
    if (k == 0) continue;
    if (b[k - 1] == 0) return false;
    for (int i = 0; i < k; i++)
      b[i]--;
  }
  for (std::vector<int>::iterator i = b.begin(); i != b.end(); i++)
    if (*i != 0)
      return false;
  return true;
}

};


int main()
{
    gfg g;
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int r,c,n,cnt=0;
    cin >> n;
    while(cnt<n){
        cnt++;
    cin >> r >> c;
    int x;
      vector<int> a;
      vector<int> b;
    for(int i=0;i<r;i++){
            cin >> x;
          a.push_back(x);
    }

    for(int j=0;j<c;j++){
          cin >> x;
          b.push_back(x);
    }



    if(g.satisfiable(a,b)) cout << "YES\n";
    else cout << "NO\n";
    }

    return 0;
}

Tried making function inline, tried cin.TIE(NULL), tried ios_base::sync_with_stdio(false);