我的错误代码能AC！

#include <iostream>
using namespace std;
int m[105][105] = {}, n;
int f[4][2] = {0, 1, 1, 0, 0, -1, -1, 0};
void bfs(int x, int y) {
	int a[10005][3] = {};
	int head = 0, tail = 0;
	a[tail][0] = x;
	a[tail][1] = y;
	m[x][y] = 2;
	tail++;
	while (head < tail) {
		for (int i = 0; i < 4; i++) 
		{
			int xx = f[i][0] + a[head][0], yy = f[i][1] + a[head][1];
			if (m[xx][yy] == 0 && xx >= 1 && xx <= n && yy >= 1 && yy <= n) 
			{
				a[tail][0] = xx;
				a[tail][1] = yy;
				tail++;
				m[xx][yy] = 2;
			}

		}
		head++;
	}
}
int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) 
	{
		for (int j = 1; j <= n; j++) 
		{
			cin >> m[i][j];
		}
	}
	bool b = true, c = false, d = 0;
	for (int i = 1; i <= n; i++)
	{
		for (int j = 1; j <= n; j++) 
		{
			if (m[i][j] == 1 && b)
				b = 0;
			else if (m[i][j] == 0 && b == 0) {
				for (int k = j; k <= n; k++) 
				{
					if (m[i][k] == 1)
						d = 1;
				}
				if (d && i > 1) 
				{
					bfs(i, j);
					c = true;
					break;
				} 
			else continue;
			}
		}
		if (c)
			break;
		else 
			b = 1;
	}
	for (int i = 1; i <= n; i++) 
	{
		for (int j = 1; j <= n; j++) 
		{
			cout << m[i][j] << " ";
		}
		cout << endl;
	}
	return 0;
}