URAL 1033 Labyrinth (DFS)

#include<stdio.h>

#define MAX 35

int size;
int M[MAX][MAX];
int visited[MAX][MAX];
int numOfWalls;
int direction[4][2] = { -1, 0, 1, 0, 0, -1, 0, 1};

void DFS(int x, int y){
	if (M[x][y] == 1 || visited[x][y] || x < 1 || x > size || y < 1 || y > size)
		return;
	visited[x][y] = 1;
	numOfWalls += M[x - 1][y] + M[x + 1][y] + M[x][y - 1] + M[x][y + 1];
	int indexOfDirection;
	for (indexOfDirection = 0; indexOfDirection < 4; indexOfDirection++)
		DFS(x + direction[indexOfDirection][0], y + direction[indexOfDirection][1]);
}

int main(){

	scanf("%d", &size);
	int row, column;
	for (row = 0; row <= size + 1; row++)
		for (column = 0; column <= size + 1; column++)
			M[row][column] = 1;
	
	for (row = 1; row <= size; row++){
		for (column = 1; column <= size; column++){
			char c;
			scanf(" %c", &c);
			if (c == '.')
				M[row][column] = 0;
		}
	}

	DFS(1, 1);
	DFS(size, size);

	printf("%d", (numOfWalls - 4)  * 9);

	return 0;
}