There is task to calculate the room area in matrix. first inputs are the coordinates of row and column position - the zeros are free space, 1 - are the walls. The problem is that flood fill function gives me Stack overflow exception.
#include<iostream>
#include<conio.h>
using namespace std;
int a[5][5] = { {0,0,1,0,0},
{0,0,1,0,0},
{0,0,1,1,1},
{1,1,1,0,0},
{0,0,1,0,0},
};
bool vis[5][5] = { {0,0,0,0,0},
{0,0,0,0,0},
{0,0,0,0,0},
{0,0,0,0,0},
{0,0,0,0,0},
};
int c = 0;
void flood(int row, int col){
if(row < 0 || row > 4 || col < 0 || col > 4)
return;
if(a[row][col] == 0 && !vis[row][col]){
c++;
vis[row][col] = 1;
}
flood(row-1, col);
flood(row+1, col);
flood(row,col-1);
flood(row, col+1);
}
int main(){
int row, column;
cin>>row>>column;
flood(row,column);
cout<< c;
getch();
return 0;
}
You shouldn't recurse if you hit a field that you already visited.
In your code, that means that hitting the !vis[row][col]
clause should prevent further recursive calls to flood
. You can achieve that simply by moving them inside the if
(or perhaps a bit more clearly, moving everything outside and flipping the condition). This will also prevent the recursion from happening when you hit a wall, but that's also what you want.