存一个数位dp的模板

记忆化搜索解数位dp方便快捷见效快。。。。

const int MAX_DIGITS, MAX_STATUS;LL f[MAX_DIGITS][MAX_STATUS], bits[MAX_DIGITS];LL dfs(int position, int status, bool limit, bool first){  if (position == -1)    return s == target_status;  if (!limit && !first && ~f[position][status])    return f[position][status];  int u = limit ? bits[position] : MAX_BITS;  LL ret = 0;  for (int i = 0; i <= u; i++)  {    ret += dfs(position - 1, next_status(status, i), limit && i == u, first && !i);  }  return limit || first ? ret : f[pos][status] = ret;}LL calc(LL 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);  LL a, b;  while (cin >> a >> b)    cout << calc(b) - calc(a - 1) << endl;  return 0;}