In this HackerRank Counting Sort 1 problem, you have given a list of integers, count and return the number of times each value appears as an array of integers.

Problem description :

Given a list of integers, count and return the number of times each value appears as an array of integers.

Input = [1, 1, 3, 2, 1] Output = [0, 3, 1, 1]

In input, we have three occurrence of 1, one occurrence of 2 and one occurrence of 3. So in output put 3 at first index, 1 at second index and 1 at third index.

Input = [2, 2, 1, 6, 5] Output = [0, 1, 2, 0, 0, 1, 1]

In this problem, we does not have to write entire code of counting sort. we need only first step of counting sort algorithm.

Counting Sort 1 Hacker Rank Solution

Problem solution in C++ programming:

vector<int> countingSort(vector<int> arr) {
    
    int max = *max_element(arr.begin(),arr.end());
    vector<int> result(max+1,0);

    for(const auto& i:arr)
        result[i]++;
     
     return vector<int>(result.begin(), result.begin()+100);
}

Problem solution in Python programming:

def countingSort(arr):
    # Write your code here
    ct=[0 for x in range(100)]
    for i in arr:
            ct[i] += 1
    return ct

Problem solution in JavaScript programming:

function countingSort(arr) {
    const freq = Array(100).fill(0);
    
    for (let elm of arr) {
        freq[elm] += 1
    }
    
    return freq;
}

Problem solution in Java programming:

  List<Integer> response = new ArrayList<>();
    for (int i = 0; i < 100; i++) {
        response.add(0);
    }

    for (Integer i : arr) {
        response.set(i, response.get(i) + 1);
    }
    return response;

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