#include<bits/stdc++.h>
int a[1005][1005];
int m;
using namespace std;
int main() {
    cin >> m;
    int k = 1, mid = 1;
    a[0][0] = 1;
    while (k <= m) {
        for (int i = 0; i < mid; i++) {
            for (int j = 0; j < mid; j++) {
                a[i][j + mid] = a[i][j] + mid;
            }
        }
        for (int i = 0; i < mid; i++) {
            for (int j = 0; j < mid; j++) {
                a[i + mid][j] = a[i][j + mid];
                a[i + mid][j + mid] = a[i][j];
            }
        }
        mid *= 2;
        k++;
    }
    for (int i = 0;i < m; i++) {
        for (int j = 0; j < m; j++) {
            cout << setw(4) << a[i][j];
        }
        cout << endl;
    }
    return 0;
}

为什么会runtime error？