// vim: set ts=2 sw=2 et tw=80:

#include <cassert>
#include <map>

class checker {
  struct pos {
    unsigned x;
    unsigned y;
    pos(unsigned x, unsigned y) : x(x), y(y) {};
  };

  unsigned c;
  unsigned r;
  std::map<pos, bool> map;

  public:
    checker(unsigned c, unsigned r) : c(c), r(r), map() {}

    void visit(unsigned int x, unsigned int y);
    bool visited(unsigned x, unsigned y);
};

void checker::visit(unsigned x, unsigned y) {
  this->map[pos(] = true;
}

bool checker::visited(unsigned x, unsigned y) {
  return this->map[x * this->c + y];
}

int main() {
  checker a(10, 10);
  a.visit(1, 1);
  assert(a.visited(1,1));
  assert(!a.visited(1,0));
}