redundant

#include <iostream>

using namespace std;
int conta_occ(int V[], int len, int x, int i = 0) {
  if (len == i) return 0;
  if (V[i] == x) return 1 + conta_occ(V, len, x, i + 1);

  return conta_occ(V, len, x, i + 1);
}

bool is_redundant(int V[], int len, int i = 0) {
  if (len == i) return true;
  if (conta_occ(V, len, V[i]) != 2) {
    return false;
  }

  return is_redundant(V, len, i + 1);
}


int main() {
  int arr[] = {1, 1, 4, 4, 5, 3, 3, 5 };

  cout << is_redundant(arr, sizeof(arr) / sizeof(arr[0]));
  return 0;
}