3. The combination of the count
1.ARC102E
The proposed limit current corresponding to each tuple.
Digital enumeration how many bins and appeared, then the problem is that each group in a second election.
The number that appears may appear $> $ 0 times, numbers not in any tuple can appear $ \ geq 0 $ times.
What can be unified method of direct flapper.
2. Small Z gifts
For the first time by the min-max all inclusion and exclusion appears conversion.
Because there $ E = \ frac {1} {P} $, then the total number of neighboring grid, so long as the number of statistics for each set of adjacent grid can overburden.
So a whole contour dp get away.
3.ARC096E
By binomial inversion to the inclusion-exclusion out of the third limit.
And then found not handpicked elements can be directly subtracted statistics.
Imperial elements is limited to $ \ leq 1 $, put enumerate how many collection, then a bit like Stirling numbers of second kind, but there is a case that the number of occurrences as $ 0 $.
I found a new collection represents the element can not appear.