how to get top N distinct elements from range?

[bearophile]

> You expect that output to contain only 5 stars.

Better seen with this code:


import std.stdio, std.range, std.algorithm, std.traits, 
std.random;

auto distinct(Range)(Range r) if (isInputRange!Range) {
     bool[ForeachType!Range] mySet;

     return r.filter!((k) {
         if (k in mySet)
             return false;
         mySet[k] = true;
         return true;
     });
}

void main() {
     5.iota.map!((_) {
         auto x = uniform(0, 10);
         write("*");
         return x;
     }).distinct.array;
}


Bye,
bearophile