Top k most frequent elements

#1

#include
#include
#include <unordered_map>
#include
using namespace std;

void Ktop(int *arr, int n, int k) {
vector top(k+1);
unordered_map<int, int> freq;
for(int m=0;m<n;m++) {
freq[arr[m]]++;
top[k] = arr[m];
auto it = find(top.begin(), top.end()-1, arr[m]);
for(int i=distance(top.begin(), it)-1;i>=0;i–) {
if(freq[top[i]]<freq[top[i+1]]) {
swap(top[i], top[i+1]);
} else if(freq[top[i]]==freq[top[i+1]] and top[i]>top[i+1]) {
swap(top[i], top[i+1]);
} else {
break;
}
}
for (int i = 0; i < k && top[i] != 0; ++i)
cout << top[i] << ’ ';
}

cout<<endl;

}
i tried but could not able to understand the code at all,can anyone please walk me through the code

#2

@dare_devil_007 please share the code by saving it on cb ide and also share the source of this code.
Also, this question can be solved easily using a priority queue in O(n) time.

1 Like
#3


Source :heap Lesson exercise Question
top k frequent elements in a stream of integers

i just did not get what was given in tutorial

#4

@dare_devil_007 refer to this article the approach has been explained properly and the code is commented so you shouldnt have any trouble understanding it. Let me know if any doubt persists.

1 Like
#5

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