求助 哪错了全wa

#include<iostream>
using namespace std;

int main() {
    int n, s, count = 1;
    cin >> n;
    int f = -1;
    const char* a;
    for (int i = 0; i < n * n; i += s) {
        cin >> s;
        for (int j = 0; j < s; j++)
        {
            a = f==1 ? "1 " : "0 ";
            cout << a;
            if (count % n == 0)
                cout << endl;
            count++;
        }
        f *= -1;

    }

}