#include "robot.h"
#include <bits/stdc++.h>
using namespace std;
enum Id {
Bound = -2,
Block,
Empty,
Path,
West,
South,
East,
North,
Imp,
};
array<char,4> dirs{{'W','S','E','N'}};
pair<int,char> IMP = {Imp,'T'};
pair<int,char> move(array<int,5> S) {
auto [h,w,s,e,n] = S;
if (h == Empty) {
if (w == Bound && n == Bound) {
// start BFS phase
if (s == Empty) {
return {South,'S'};
} else {
return {East,'E'};
}
} else if (e == Bound && s == Bound) {
// start pruning phase
return {East,'H'};
} else {
// extend tree
for (int i = 0; i < 4; ++i) {
if (S[i+1]-West == (i+2)%4) return {West+i,dirs[i]};
}
return IMP;
}
} else if (0 <= h-West && h-West < 4) {
int dir = h-West;
if (S[dir+1]-West == (dir+2)%4) {
// traverse tree
int i = dir;
do {
i = (i+1)%4;
if (S[i+1]-West == (i+2)%4 || S[i+1] == Empty) return {West+i,dirs[i]};
} while (i != dir);
return IMP;
} else {
// pruning phase
int i = dir;
bool path = false;
do {
i = (i+1)%4;
// traverse to tile other than previous
if (S[i+1]-West == (i+2)%4) return {h,dirs[i]};
if (S[i+1] == Path) path = true;
} while (i != dir);
// prune
return {
path || (w == Bound && n == Bound) ? Path : Empty,
e == Bound && s == Bound ? 'T' : dirs[i],
};
}
} else {
return IMP;
}
}
#define FR(x) for (int x = Bound; x < Imp; ++x)
void program_pulibot()
{
FR(h) FR(w) FR(s) FR(e) FR(n) {
auto [Z,A] = move({h,w,s,e,n});
set_instruction({h,w,s,e,n}, Z, A);
}
}
