This function returns the number of distinct contexts in a context tree.

## Arguments

- ct
a context tree.

## Value

the number of contexts of the tree.

## Examples

```
dts <- c(0, 1, 1, 1, 0, 0, 1, 0, 1, 0)
dts_ctree <- ctx_tree(dts, min_size = 1, max_depth = 3)
# should be 8
context_number(dts_ctree)
#> [1] 8
```