Top K Frequent Elements Using Heap in DSA Go - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a map to count frequencies of elements.

DSA Go

freqMap := make(map[int][1])

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Aint

Bstring

Cfloat64

Dbool

Attempts:

3 left

💡 Hint

Common Mistakes

Using string or bool as map value type instead of int.

Forgetting to initialize the map.

The frequency map stores counts as integers, so the value type must be int.

2fill in blank

medium

Complete the code to push an element with its frequency into the heap.

DSA Go

heap.Push(&h, [1]{num: num, freq: freqMap[num]})

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Aelement

Bpair

Cnode

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect struct names like element or node.

Not passing the address of the heap.

The heap stores pair structs containing the number and its frequency.

3fill in blank

hard

Fix the error in the heap comparison function to create a max-heap by frequency.

DSA Go

func (h pairHeap) Less(i, j int) bool {
    return h[i].freq [1] h[j].freq
}

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A<

B!=

C==

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' creates a min-heap, which is incorrect here.

Using '==' or '!=' does not order elements properly.

To create a max-heap by frequency, the element with higher frequency should be 'less' so it comes first, so use >.

4fill in blank

hard

Fill both blanks to pop the top element from the heap and append its number to the result slice.

DSA Go

top := heap.[1](&h).([2])
result = append(result, top.num)

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APop

BPush

Cpair

DRemove

Attempts:

3 left

💡 Hint

Common Mistakes

Using Push instead of Pop.

Not type asserting the popped value.

Use heap.Pop to remove the top element and type assert it to pair.

5fill in blank

hard

Fill all three blanks to build the frequency map, push all pairs into the heap, and initialize the heap.

DSA Go

freqMap := make(map[int]int)
for _, num := range nums {
    freqMap[num] = freqMap[num] [1] 1
}
h := pairHeap{}
for num := range freqMap {
    heap.[2](&h, pair{num: num, freq: freqMap[num]})
}
heap.[3](&h)

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A+=

BPush

CInit

D-=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-=' instead of '+=' for counting.

Forgetting to call heap.Init before popping.

Using wrong heap functions.

Increment frequency with +=, push pairs with heap.Push, and initialize heap with heap.Init.