228

for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++)
    a[i][j] = (i + j)%2, k[(i + j)%2][i]++;
    int b = 0, w = 0;
    for (int i = 1; i <= n; i++)
        b += k[1][i];
    vector<int> x;
    for (int i = 0; i <= n; i++){
        b -= k[1][i];
        w += k[0][i];
        x.pb(b + w);
    }