Solution2.cpp

class Solution {
public:
    int numberOfStableArrays(int zero, int one, int limit) {
        const int mod = 1e9 + 7;
        using ll = long long;
        ll f[zero + 1][one + 1][2];
        memset(f, 0, sizeof(f));
        for (int i = 1; i <= min(zero, limit); ++i) {
            f[i][0][0] = 1;
        }
        for (int j = 1; j <= min(one, limit); ++j) {
            f[0][j][1] = 1;
        }
        for (int i = 1; i <= zero; ++i) {
            for (int j = 1; j <= one; ++j) {
                f[i][j][0] = (f[i - 1][j][0] + f[i - 1][j][1]
                                 - (i - limit - 1 < 0 ? 0 : f[i - limit - 1][j][1]) + mod)
                    % mod;
                f[i][j][1] = (f[i][j - 1][0] + f[i][j - 1][1]
                                 - (j - limit - 1 < 0 ? 0 : f[i][j - limit - 1][0]) + mod)
                    % mod;
            }
        }
        return (f[zero][one][0] + f[zero][one][1]) % mod;
    }
};