Maze

#include<iostream>
#include <cstring>
#include<cstdio>

using namespace std;

int n;
int Sum = 0 ;
int ans = 0 ;

int dJx[4] = { 		-1	, 	0	, 	1	, 	0	};
int dJy[4] = { 		0	, 	1	, 	0	, 	-1	};

struct node {
	int x;
	int y;
	int num;
};

node a[10002];
node b[10002];

char Map[102][102];
bool bo_F [102][102];
bool bo_J [102][102];

bool Check1 ( int x , int y ) {
	return x>0 && x<=n && y>0 && y<=n ;
}

bool Check2(int i,int j) {
	return ( a[i].x == b[j].x && ( a[i].y == b[j].y || a[i].y-1 == b[j].y || a[i].y+1 == b[j].y ) ) || ( a[i].y == b[j].y && ( a[i].x == b[j].x || a[i].x-1 == b[j].x || a[i].x+1 == b[j].x ) );
}

int main() {
	freopen("maze.in","r",stdin);
	freopen("maze.out","w",stdout);

	int Fx,Fy,Jx,Jy;

	memset ( bo_J , true , sizeof bo_J );
	memset ( bo_F , true , sizeof bo_F );

	cin >> n ;

	for ( int i = 1 ; i <= n ; i ++ )
		for ( int j = 1 ; j <= n ; j ++ ) {
			cin >> Map[i][j];

			if ( Map[i][j] == 'F' ) {
				Fx = i ;
				Fy = j ;
			}
			if ( Map[i][j] == 'J' ) {
				Jx = i ;
				Jy = j ;
			}
			if ( Map[i][j] != '*' ) Sum ++ ;

		}

	int qhead = 1 ;
	int qtail = 1 ;
	int s = 0 ;
	int k = 0;

	a[1].x = Jx;
	a[1].y = Jy;
	a[1].num = 1;
	bo_J[Jx][Jy] = false ;

	while ( qhead <= qtail && k <= Sum ) {

		for ( int i = 0 ; i < 4 ; i ++  ) {

			int d = ( i + s ) % 4 ;
			int x = a[qhead].x + dJx[d] ;
			int y = a[qhead].y + dJy[d] ;

			if ( Map[x][y] != '*' && Check1( x  ,y ) ) {
				qtail ++ ;
				a[qtail].x = x;
				a[qtail].y = y;
				a[qtail].num = a[qhead].num + 1 ;
				s = ( i + s ) % 4 ;
				k ++ ;
				break;
			}

		}

		qhead ++ ;

	}

	int len_J = qtail ;
	qhead = 1 ;
	qtail = 1 ;
	b[1].x = Fx;
	b[1].y = Fy;
	b[1].num = 1;
	bo_F[Fx][Fy] = false ;

	while ( qhead <= qtail ) {

		for ( int i = 0 ; i < 4 ; i++ ) {

			int x = b[qhead].x + dJx[i] ;
			int y = b[qhead].y + dJy[i] ;

			if ( bo_F[x][y] && Map[x][y] != '*' && Check1 ( x , y ) ) {

				bo_F[x][y] = false ;
				qtail ++ ;
				b[qtail].x = x;
				b[qtail].y = y;
				b[qtail].num = b[qhead].num + 1 ;
			}
		}
		++qhead;
	}

	int len_F = qtail ;
	/*
	for (int i=1;i<=len_J;++i){
		cout << a[i].num << ' ';
	}
	
	cout << endl;
	for (int j=1;j<=len_F;++j){
		cout << b[j].num << ' ';
	}
	cout << endl;
	*/

	for ( int i = 1 , j = 1 ; i <= len_J , j <= len_F ; ) {
		while ( a[i].num != b[j].num ) {
			if ( a[i].num > b[j].num )
				j++;
			else i++;
		}

		if (Check2(i,j)) {
			cout << a[i].num - 1 << endl ;
			return 0;
		} else j ++ ;
	}

	cout << "No solution" << endl ;

	return 0 ;

}