windy数

int f[20][10], bits[20];

int dfs(int pos, int pre, bool lmt, bool first)
{
    if (pos == -1) return 1;
    if (!lmt && ~f[pos][pre]) return f[pos][pre];
    int u = lmt ? bits[pos] : 9, ret = 0;
    for (int i = 0; i <= u; i++)
    {
        if (first || (!first && abs(pre - i) >= 2))
            ret += dfs(pos - 1, i, lmt && i == u, first && !i);
    }
    return lmt || first ? ret : f[pos][pre] = ret;
}

int calc(int n)
{
    CLR(f, -1);
    int len = 0;
    while (n)
    {
        bits[len++] = n % 10;
        n /= 10;
    }
    return dfs(len - 1, 0, true, true);
}

int main()
{
    //freopen("0.txt", "r", stdin);
    int a, b;
    while (~RII(a, b))
    {
        cout << calc(b) - calc(a - 1) << endl;
    }
    return 0;
}