you are given one stream and you have to sort them based on element frequency and if frequency are same then sort based on value and. print value upto k if stream reach k thresold then remove less frequncy element first if freq same for all then remove old element (which comes first in stream).
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for example :

given steam: add(7), add(4), add(8), add(2), add(6), add(7), k = 3
output: [7], [4,7], [4,7,8], [2,4,8], [2,6,8], [7,2,6,]

explaination:
-> [7] - add 7
-> [4,7] - add 4 as both elem frequency same so sort based on value
-> [4,7,8] - add 8 again all elem freq are same so sort by value
-> [2,4,8] - adding 2 will reach k thresold then remove lower frequency elem first if freq are same then remove elem which come first so remove 7 and add 2.
-> [2,6,8] - adding 6 again reach thresold so remove whichever come first in this 4
-> [7,2,6] -> adding 7 will reach 7 frequency = 2, which is more then others so, it comes first and so on..