How To Approach this Question

#1

Given an array of n numbers. Your task is to read numbers from the array and keep at-most K numbers at the top (according to their decreasing frequency) every time a new number is read. We basically need to print top k numbers sorted by frequency when input stream has included k distinct elements, else need to print all distinct elements sorted by frequency. If frequency of two numbers are same then print them in increasing order.

Input Format
First line contains integer t as number of test cases. Each test case contains following input. First line contains integer n and k, n represents the length of the array and next line contains n space separated integers.

#2

Hi @ayush_r18
Iterate through the array which contains stream of numbers.
To keep track of top k elements, make a top vector of size k+1.
For every element in the stream increase its frequency and store it in the last position of top vector. We can use hashing for efficiently fetching frequency of an element and increasing it.
Now find the position of element in top vector and iterate from that position to zero. For finding position we can make use of the find() function in C++ STL, it returns an iterator pointing to element if found in the vector.
And make that list of k+1 numbers sorted according to frequency and their value.
Print top k elements form top vector.
Repeat the above steps for every element in the stream.

Try keeping these steps in mind you will be able to solve it If you still face any issue please let me know

#3

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