1からnまでの乱数をm個重複せずO(m)でランダムに選ぶrubyのプログラム。 choose m integers from 1 to n randomly

random.rb

def rands(n,m)
    result=[]
    memo  ={}
    m = n if n < m
    1.upto(m){|low|
        v = rand(low..n)
        if !memo[v]
            result << v
            memo[v] = memo[low] || low
        else
            result << memo[v]
            memo[v] = memo[low] || low
        end
    }
    return result
end

100.times{
    puts rands(10,5)*" "
}