不管输入是什么输出都是0，找了好久找不到问题

#include<iostream>
#include<cstdio>
using namespace std;
int m[2000][2000], n;
void dfs(int x,int l,int r) {
	if (x == 2) {
		m[l][r] = 0;
		return;
	}
	else {
		x = x / 2;
		for (int i = l; i <= l + x - 1; i++) {
			for (int j = r; j <= r + x - 1; j++) {
				m[l][r] = 0;
			}
		}
		dfs(x, l + x, r);
		dfs(x, l + x, r + x);
		dfs(x, l, r + x);
	}
}
int main()
{
	cin >> n;
	n = pow(2,n);
	memset(m, sizeof(m), 1);
	dfs(n, 1, 1);
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n-1; j++) {
			cout << m[i][j]<<" ";
		}
		cout << m[i][n] << endl;
	}
	return 0;
}

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