How to define a constraint in Ortools to set a limit of distinct values

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I am trying to define a constraint that is going to limit the number of unique values generated by the solver. It can generate as many duplicates as possible to solve the problem but there is a limit on unique values.

or-tools linear-programming constraint-programming c#
1 Answers

For each value, create a boolean variable selected_value that is true iff at least one value is assigned to it.

For this you will need 2 sets of constraints:

from left to right: selected_value implies the value is selected

model.AddBoolOr([var_i_equals_value, ...]).OnlyEnforcedIf(selected_value)

and from right to left, the value is selected implies selected_value is true

for var_i_equals_value in ...:
    model.AddImplication(var_i_equals_value, selected_value)

And then you just need to constraint the sum of the selected values

model.Add(sum(selected_value_array) <= 10)

Now you need to ask if you really need integer variables, or just a matrix of Boolean variables. I suggest the latter.

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