347. Top K Frequent Elements

Description:

Solution:

 

count is the dictionary for heap. 

We go through the nums, and counting. If the number doesn't exist, get(0). 

And then, from hash table, we put the values in freq[[]] to see how many counts they have.

 

Since the freq[[]] is descending order, we go through reverse order. We put the highest count to lowest count.

We append the higest number of count in res[].  End the loop if we get the number of k highest value.

 

Time Complexity: O(n)

Space Complexity: O(n)