32 SOS

#include <bits/stdc++.h>
using namespace std;
int n;
int a[40][40];
int b[40][40];
int xf[4] = {1, -1, 0, 0};
int yf[4] = {0, 0, -1, 1};
void dfs(int x, int y) {

    if (x >= 1 && x <= n && y >= 1 && y >= n && b[x][y] == 0) {
        b[x][y] = 1;
        for (int i = 0; i < 4; i++) {

            if (a[x + xf[i]][y + yf[i]] == 0) {

                dfs(x + xf[i], y + yf[i]);

            }

        }
    }
}

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {

        for (int j = 1; j <= n; j++) {

            cin >> a[i][j];
            b[i][j] = a[i][j];
        }

    }

    dfs(1, 1);
    dfs(1, n);
    dfs(n, 1);
    dfs(n, n);

    for (int i = 1; i <= n; i++) {

        for (int j = 1; j <= n; j++) {
            if (b[i][j] == 0) a[i][j] = 2;
            cout << a[i][j] << " ";
        }
        cout << endl;
    }

}