N Queens problem

#include <bits/stdc++.h>
#define endl '\n'
typedef long long ll;
using namespace std;


const int N = 8;
int total = 0;

void print(vector<int> &v) {
  cout << "{\n";
  for (int i = 0; i < N; ++i) {
    cout << "  {";
    for (int j = 0; j < N; ++j) {
      cout << (v[i] == j) << ", ";
    }
    cout << "},\n";
  }
  cout << "},\n";
}


void f(vector<int> v, int row) {
  if (row == N) {
    total++;
    print(v);
    return;
  }
  for (int col = 0; col < N; ++col) {
    bool ok = 1;
    for (int i = 0; i < row; ++i) {
      int j = v[i];
      if (j == col || row+col == i+j || row-col == i-j) {
        ok = 0;
        break;
      }
    }
    if (ok) {
      v[row] = col;
      f(v, row+1);
    }
  }
}

void start() {
  vector<int> v(N, -1);
  for (int j = 0; j < N; ++j) {
    v[0] = j;
    f(v, 1);
  }
}

void main1() {

  start();
  cout << "Total amount: " << total << endl;

}






int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  std::cout.tie(nullptr);
  #ifdef _DEBUG
  std::freopen("in.txt", "r", stdin);
  std::freopen("out.txt", "w", stdout);
  #endif
  main1();
}