#include <bits/stdc++.h>
#include "robot.h"
using std::size_t;
const int unexplored = 0;
const int stroke = 1;
const int red_start = 2;
const int blue_start = 6;
const int unmark = 10;
inline int red(int parent) { return red_start - 1 + parent; }
inline int blue(int parent) { return blue_start - 1 + parent; }
inline bool is_red(int state) { return state >= red_start && state < red_start + 4; }
inline bool is_blue(int state) { return state >= blue_start && state < blue_start + 4; }
inline int parent(int state) { return (state - 2) % 4 + 1; }
inline int reverse(int dir)
{
if (dir == 0)
return 0;
return (dir - 1 + 2) % 4 + 1;
}
const int max_color = 10;
const int min_color = 0;
const int min_state = -2;
const int obstacle = -1;
const int border = -2;
const std::array<char, 5> actions = {'H', 'W', 'S', 'E', 'N'};
#define FOR_STATE_VALUES(i) for (int i = min_state; i <= max_color; i++)
void set_instruction(std::array<int, 5> const &state, int color, char action)
{
set_instruction(std::vector<int>(state.begin(), state.end()), color, action);
}
void program_state(int h, int w, int s, int e, int n)
{
std::array<int, 5> state = {h, w, s, e, n};
bool is_start = w == border && n == border;
bool is_end = e == border && s == border;
bool is_retracing = is_end;
bool is_unmarking = false;
for (int d = 1; d <= 4; d++)
{
if (state[d] == stroke)
is_retracing = true;
if (state[d] == unmark)
is_unmarking = true;
}
if (is_unmarking)
{
for (int d = 1; d <= 4; d++)
if ((is_red(state[d]) || is_blue(state[d])) && parent(state[d]) == reverse(d))
return set_instruction(state, unmark, actions[d]);
for (int d = 1; d <= 4; d++)
if (state[d] == unmark)
return set_instruction(state, unexplored, actions[d]);
}
if (h == unmark)
{
for (int d = 1; d <= 4; d++)
if (is_blue(state[d]))
return set_instruction(state, unmark, actions[d]);
int red_count = 0;
for (int d = 1; d <= 4; d++)
if (is_red(state[d]))
red_count++;
if (red_count == 1 && !is_start)
for (int d = 1; d <= 4; d++)
if (is_red(state[d]))
return set_instruction(state, stroke, actions[d]);
if (red_count == 0)
return set_instruction(state, stroke, 'T');
for (int d = 1; d <= 4; d++)
{
if (!is_red(state[d]))
continue;
for (int offset = 1; offset <= 3; offset++)
{
int prev = (d - 1 - offset + 4) % 4 + 1;
if (is_red(state[prev]))
break;
if (state[prev] == unexplored)
return set_instruction(state, unmark, actions[d]);
}
}
}
if (is_retracing)
{
if (is_red(h))
{
for (int offset = 1; offset <= 3; offset++)
{
int d = (parent(h) + offset - 1) % 4 + 1;
if (is_red(state[d]) || is_blue(state[d]))
return set_instruction(state, unmark, actions[d]);
}
if (is_start)
return set_instruction(state, stroke, 'T');
return set_instruction(state, stroke, actions[parent(h)]);
}
if (h == unexplored)
for (int d = 1; d <= 4; d++)
if (is_red(state[d]))
return set_instruction(state, stroke, actions[d]);
}
if (is_start && h == unexplored)
return set_instruction(state, red(1), 'H');
if (h == unexplored)
{
for (int d = 1; d <= 4; d++)
if (is_red(state[d]))
return set_instruction(state, blue(d), actions[d]);
}
if (is_red(h))
{
for (int d = 1; d <= 4; d++)
if (state[d] == unexplored || (is_red(state[d]) && parent(state[d]) == reverse(d)))
return set_instruction(state, h, actions[d]);
if (is_start)
return set_instruction(state, blue(1), 'H');
else
return set_instruction(state, blue(parent(h)), actions[parent(h)]);
}
if (is_blue(h))
{
for (int d = 1; d <= 4; d++)
if (is_blue(state[d]) && parent(state[d]) == reverse(d))
return set_instruction(state, h, actions[d]);
if (is_start)
return set_instruction(state, red(1), 'H');
else
return set_instruction(state, red(parent(h)), actions[parent(h)]);
}
}
void program_pulibot()
{
FOR_STATE_VALUES(h)
FOR_STATE_VALUES(w)
FOR_STATE_VALUES(s)
FOR_STATE_VALUES(e)
FOR_STATE_VALUES(n)
program_state(h, w, s, e, n);
}
