# Find all semistandard Young tableaux with the same content as a given tableau.

Let T be a semistandard tableau, for example [[1,3,5],[2,4,9]] (columns). I want to find all semistandard tableaux with the same shape and with the same content as T, which is 1,2,3,4,5,9 (the content can be a multi-set). For example, [[1,2,4],[3,5,9]] (columns) is one of such semistandard tableaux.

I can list all semistandard Young tableaux with maximal number 9:

```
list(SemistandardTableaux([2,2,2], max_entry=9))
```

and then select those with the same content as T. But this is slow when T is large. Is there faster way to do this? Thank you very much.