Find some long-distance boards

[slidingtile] / find_long_distance_boards.cc

#include "sliding_tile_lib.h"
#include "gflags/gflags.h"

#include <iostream>
#include <random>

int main(int argc, char** argv) {
  gflags::ParseCommandLineFlags(&argc, &argv, false);

  Board goal{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}};
  InvertedBoard invgoal = goal.invert();

  Board rev{{0,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1}};
  std::cout << rev.distance(invgoal) << ": " << rev << std::endl;

  std::random_device rd;
  std::mt19937 rng(rd());

  int max_distance = 0;
  while (true) {
    Board b{{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}};
    for (int i = 0; i < BOARD_SIZE; i++) {
      std::uniform_int_distribution<> get_random_number(0, i);
      std::swap(b.board[i], b.board[get_random_number(rng)]);
    }
    int dist = b.distance(invgoal);
    if (dist > max_distance) {
      max_distance = dist;
    }
    if (dist > max_distance - 2) {
      std::cout << dist << ": " << b << std::endl;
    }
  }
}