infoarena informatica de performanta

#include<fstream>
#include<queue>


using namespace std;

ifstream fin("alee.in");
ofstream fout("alee.out");

int di[4] = { 0, 0,1, -1 };
int dj[4] = { 1, -1, 0, 0 };
int map[180][180];
int N, M, startx, starty, endx, endy;
queue<pair<int, int>> myQueue;

void read()
{
	int x, y;	
	fin >> N >> M;
	for(int i=0;i<M;i++)
	{
		fin >> x >> y;
		map[x][y] = -1;	
	}
	fin >> startx >> starty;
	fin >> endx >> endy;
}

bool ok(int i, int j)
{
	if (i<1 || j<1 || i>N || j>N)
		return false;
	if (map[i][j] == -1)
		return false;
	return true;
}

void Lee()
{
	int i, j, nexti, nextj;
	map[startx][starty] = 1;
	myQueue.push(make_pair(startx, starty));
	while (!myQueue.empty())
	{
		i = myQueue.front().first;
		j = myQueue.front().second;
		myQueue.pop();
		for(int dir=0;dir<=3;dir++)
		{
			nexti = i + di[dir];
			nextj = j + dj[dir];
			if (ok(nexti, nextj) && map[nexti][nextj] ==0)
			{
				map[nexti][nextj] = map[i][j] + 1;
				myQueue.push(make_pair(nexti, nextj));
			}
		}
	}
}

int main()
{
	read();
	Lee();
	fout << map[endx][endy];
    return 0;
}