#include "robot.h"
#include <vector>
#define pb push_back
using namespace std;
int DIRS = 4;
int WALL = -2;
int BLOCK = -1;
int EMPTY = 0;
int PATH = 1;
int MX = 14;
// If the parent of current node is neighbour i, it will be marked fresh[i - 1]
int fresh[4] = {2, 3, 4, 5};
int used[4] = {6, 7, 8, 9};
int ending[4] = {10, 11, 12, 13};
char dir[4] = {'W', 'S', 'E', 'N'};
vector<int> s;
int par, pathtile, endtile;
vector<int> avail;
// Fresh and used kids
vector<int> kids[2];
void precalc(void)
{
avail.clear();
kids[0].clear();
kids[1].clear();
par = 0;
pathtile = -1;
endtile = -1;
for (int i = 0; i < 4; i++) {
// Check if s[i] indicates that the kid has this as parent
int p = (i + 2) % 4;
if (s[i + 1] == fresh[p]) {
kids[0].pb(i);
}
else if (s[i + 1] == used[p]) {
kids[1].pb(i);
}
else if (s[0] == fresh[i] || s[0] == used[i] || s[0] == ending[i]) {
par = i;
}
if (s[i + 1] == PATH)
pathtile = i;
}
}
bool isfresh(int v)
{
for (int i = 0; i < DIRS; i++)
if (fresh[i] == v)
return true;
return false;
}
bool startcell()
{
return s[1] == WALL && s[4] == WALL;
}
bool endcell()
{
return s[2] == WALL && s[3] == WALL;
}
bool explore_neighbours(bool m)
{
if (kids[m].size()) {
set_instruction(s, s[0], dir[kids[m].front()]);
return true;
}
else {
return false;
}
}
void empty_cell()
{
if (s[0] != EMPTY)
return;
if (startcell()) {
set_instruction(s, fresh[0], 'H');
return;
}
// Find the parent which is fresh
for (int i = 0; i < DIRS; i++)
if (isfresh(s[i + 1])) {
// Mark the best path and go back
if (endcell()) {
set_instruction(s, PATH, dir[i]);
return;
}
set_instruction(s, used[i], dir[i]);
break;
}
}
void invert_state()
{
if (startcell()) {
if (s[0] == fresh[0])
set_instruction(s, used[0], 'H');
else
set_instruction(s, fresh[0], 'H');
return;
}
if (s[0] == fresh[par])
set_instruction(s, used[par], dir[par]);
else
set_instruction(s, fresh[par], dir[par]);
}
void kill_paths(bool b)
{
for (int b = 0; b < 2; b++)
for (auto k : kids[b]) {
set_instruction(s, ending[par], dir[k]);
return;
}
// Everything is killed
if (startcell()) {
set_instruction(s, PATH, 'T');
return;
}
set_instruction(s, b ? PATH : EMPTY, dir[par]);
}
void traversed_cell()
{
precalc();
if (!startcell() && (s[par + 1] >= ending[0] || s[par + 1] == PATH)) {
kill_paths(false);
return;
}
if (pathtile != -1) {
kill_paths(true);
return;
}
if (explore_neighbours(!isfresh(s[0])))
return;
if (isfresh(s[0]) && kids[0].size() == 0) {
// Find empty cells
for (int i = 0; i < DIRS; i++)
if (s[i + 1] == 0) {
set_instruction(s, s[0], dir[i]);
return;
}
}
invert_state();
}
void program_pulibot()
{
s.resize(5);
for (s[0] = -2; s[0] < MX; s[0]++)
for (s[1] = -2; s[1] < MX; s[1]++)
for (s[2] = -2; s[2] < MX; s[2]++)
for (s[3] = -2; s[3] < MX; s[3]++)
for (s[4] = -2; s[4] < MX; s[4]++) {
if (s[0] < 0)
continue;
if (s[0] == EMPTY) {
empty_cell();
}
else {
traversed_cell();
}
}
}
