test_tron.cpp

#include <iostream>
#include <vector>
#include <list>
using namespace std;
/* Head ends here */


typedef list< pair<int, int> > coordList;

void printMove(char player, int plx , int ply, int dirx, int diry, vector <string> board);
short int canFollowWall(int x, int y, vector <string> board);
coordList getAvailNeighbors(int x, int y, vector <string> board);
void basicWalking(char player,int x, int y, int o_x, int o_y, vector <string> board);

/*
 *  Takes player coordinates as well as "future" tile coordinates(also named direction)
 *  and prints the output accordingly
 *  Utility function --
 */
void printMove(char player, int plx , int ply, int dirx, int diry, vector <string> board) {
	//board.at(dirx).at(diry) = player;

	if (plx ==  dirx) {

		if(ply < diry) {
			cout << "RIGHT" << endl;
		} else {
			cout << "LEFT" << endl;
		}

	} else
	if (ply == diry) {

		if(plx < dirx) {
			cout << "DOWN" << endl;
		} else {
			cout << "UP" << endl;
		}

	}
}

/*
 * Function takes as parameters player position and the map checks if we can follow wall
 * return value :
 *  0 - no wall to follow
 *  1 - can follow vertical
 *  2 - can follow horizontal
 */


short int canFollowWall(int x, int y, vector <string> board) {

	/*
	 * vertical follow
	 */
	if(((board.at(x).at( y - 1) == '#' ) || (board.at(x).at( y + 1) == '#' )) &&
			((board.at(x + 1).at(y) == '-' ) || (board.at(x - 1).at(y) == '-' )))
		return 1;

	/*
	 * horizontal follow
	 */
	if(((board.at(x - 1).at(y) == '#' ) || (board.at(x + 1).at(y) == '#' )) &&
			((board.at(x).at( y - 1) == '-' ) || (board.at(x).at( y + 1) == '-' )))
			return 2;
	return 0;
}
/*
 * basic walking function when no wall is close, we just take first direction available
 * might be improved to some more complex logic
 */


void basicWalking(char player,int x, int y, int o_x, int o_y, vector <string> board) {

	coordList nbs = getAvailNeighbors(x,y, board);

	if(nbs.size() == 0) {
		/*
		 * We have a dead end : suicide by going up
		 */
		printMove(player, x, y, x + 1, y, board);
	} else {
		/*
		 * we take first direction available
		 */
		//left, down, right, up
		/*
		 * count == 1 <- left
		 * count == 2 <- down
		 * count == 3 <- right
		 * count == 4 <- up
		 */
		coordList::iterator iter = nbs.begin();

			int count = 0;
			for(;iter != nbs.end();iter++) {

				int n_x = (*iter).first;
				int n_y = (*iter).second;
				if ( n_x == x && n_y == y - 1) {
					count = 1;
					break;
				}
				if (n_x == x + 1 && n_y == y) {
					count = 2;
					break;
				}

				if(n_x == x && n_y == y + 1) {
					count = 3;
					break;
				}
				if(n_x = x - 1 && n_y == y) {
					count = 4;
					break;
				}

			}
			for(int i = 1; i < count; i++) {
				nbs.pop_front(); // get to the direction that we are having
			}
			printMove(player, x,y, nbs.front().first, nbs.front().second, board);
	}
}

coordList getAvailNeighbors(int x, int y, vector <string> board) {

	coordList result;

	if ((x + 1) <  board.size() - 1)
		if(board.at(x+1).at(y) == '-')
			result.push_back(make_pair(x + 1, y));
	if(( x - 1) > 0)
		if(board.at( x - 1).at(y) == '-')
			result.push_back(make_pair(x - 1, y));

	if((y + 1) < board.at(x).length() - 1)
		if(board.at(x).at(y + 1) == '-')
			result.push_back(make_pair(x, y + 1));

	if((y - 1) > 0)
		if(board.at(x).at(y - 1))
			result.push_back(make_pair(x, y - 1));

	return result;
}

void swap (int *a, int*b) {
	int aux;
	aux = *b;
	*b = *a;
	*a = aux;
}

void nextMove(char player,int x, int y, int o_x, int o_y, vector <string> board){

if(player == 'g') {
	swap(&x, &o_x);
	swap(&y, &o_y);
}

	coordList nbs = getAvailNeighbors(x,y, board);

	if (canFollowWall(x,y, board) == 0) {
		basicWalking(player, x, y, o_x, o_y, board);

	} else
	if (canFollowWall(x,y, board) == 1) {

		coordList::iterator iter = nbs.begin();

		for(;iter != nbs.end();iter++) {

			int n_x = (*iter).first;
			int n_y = (*iter).second;
			if(n_y == y) {
				printMove(player, x, y, n_x, n_y, board);
				break;
			}
		}
	} else

	if (canFollowWall(x,y, board) == 2) {
		coordList::iterator iter = nbs.begin();

		for(;iter != nbs.end();iter++) {

			int n_x = (*iter).first;
			int n_y = (*iter).second;

			if(n_x == x) {
				printMove(player, x, y, n_x, n_y, board);
				break;
			}

		}

	}

}
/* Tail starts here */
int main() {

    char player;
    int x, y;
    int o_x, o_y;
    int size_x, size_y;
    vector <string> board;

    cin >> player;
    cin >> x >> y >> o_x >> o_y >> size_x >> size_y;
    for(int i=0; i<size_x; i++) {
        string s; cin >> s;
        board.push_back(s);
    }

    nextMove(player,x,y, o_x, o_y, board);

    return 0;
}