Castle defectuosisimo

#include <iostream>
#include <vector>
#include <queue>
#define INF (1<<29)
using namespace std;

int dx[] = {-1, 1, 0, 0};
int dy[] = { 0, 0, 1,-1};

struct graf {
    vector< string > ady;
    vector < vector<int> > dist;
    int n, inicialX, inicialY, finalX, finalY;

    int x, y;

    void leer()
    {
        cin>>n;
        ady.resize(n+1);
        dist = vector< vector<int> > (n+1, vector<int> (n+1, INF) );

        string a;
        for(int i=0; i<n; i++)
        {
            cin>>a;
            ady[i]=a;
        }
        cin>>inicialX>>inicialY>>finalX>>finalY;
    }

    bool valid(const int &x, const int &y)
    {
        if ( 0<=x && x<=n && 0<=y && y<=n && ady[x][y]!='X')
            return true;
        return false;
    }

    bool mover (int x, int y, int dx, int dy, int &topex, int &topey)
    {
        int newx = x+dx;
        int newy = y+dy;
        if ( valid(newx,newy) )
        {
            if ( dist[x][y]+1 < dist[newx][newy] )
                dist[newx][newy] = dist[x][y]+1;
            mover(newx,newy,dx,dy,topex,topey);
        }
        else
        {
            topex=x;
            topey=y;
        }
    }

    int BFS ()
    {
        queue< pair<int,int> > q;

        x = inicialX;
        y = inicialY;

        q.push( {x,y} );
        dist[x][y]=0;

        while( q.size()!=0 )
        {
            x = q.front().first;
            y = q.front().second;
            q.pop();

            for (int i=0; i<4; i++)
            {
                int topex, topey;
                mover(x,y,dx[i],dy[i],topex,topey);

                if( dist[x][y]+1 < dist[topex][topey] )
                {
                    dist[topex][topey] = dist[x][y]+1;
                    q.push( {topex,topey} );
                }
            }
        }

        return dist[finalX][finalY];
    }
};

int main()
{
    graf g;
    g.leer();
    cout<<g.BFS();

    return 0;
}