Comparison Sorting

Quicksort usually has a running time of n*log(n), but is there an algorithm that can sort even faster? In general, this is not possible. Most sorting algorithms are comparison sorts, i.e., they sort a list just by comparing the elements with one another. A comparison sort algorithm cannot beat n log(n) (worst-case) running time, since n log(n) represents the minimum number of comparisons needed to know where to place each element. For more details, you can see these notes (PDF).

Alternative Sorting

However, for certain types of input, it is more efficient to use a non-comparison sorting algorithm. This will make it possible to sort lists even in linear time. These challenges will cover Counting Sort, a fast way to sort lists where the elements have a small number of possible values, such as integers within a certain range. We will start with an easy task – counting.

Challenge

Given a list of integers, can you count and output the number of times each value appears?

Hint: There is no need to sort the data, you just need to count it.

Input Format

There will be two lines of input:

n – the size of the list

ar – n space separated numbers that makes up the list

Output Format

Output the number of times every number from 0 to 99 (inclusive) appears in the list.

Constraints

100 <= n <= 106

0 <= x < 100 , x ∈ ar

Sample Input

100

63 25 73 1 98 73 56 84 86 57 16 83 8 25 81 56 9 53 98 67 99 12 83 89 80 91 39 86 76 85 74 39 25 90 59 10 94 32 44 3 89 30 27 79 46 96 27 32 18 21 92 69 81 40 40 34 68 78 24 87 42 69 23 41 78 22 6 90 99 89 50 30 20 1 43 3 70 95 33 46 44 9 69 48 33 60 65 16 82 67 61 32 21 79 75 75 13 87 70 33

Sample Output

0 2 0 2 0 0 1 0 1 2 1 0 1 1 0 0 2 0 1 0 1 2 1 1 1 3 0 2 0 0 2 0 3 3 1 0 0 0 0 2 2 1 1 1 2 0 2 0 1 0 1 0 0 1 0 0 2 1 0 1 1 1 0 1 0 1 0 2 1 3 2 0 0 2 1 2 1 0 2 2 1 2 1 2 1 1 2 2 0 3 2 1 1 0 1 1 1 0 2 2

Explanation

the output states that 0 appears 0 times.

1 appears 2 times.

2 appears 0 times.

and so on in the given input array.

Copyright (c) 2015 HackerRank.

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Suggest Edits

6362 hackers have submitted code

#include
#include
#include
#include
int main() {
int N,i,arr[100]={0},V;
scanf("%d",&N);
while(N--)
{
scanf("%d",&V);
arr[V] +=1;
}
for(i=0;i<100;i++)
{
printf("%d ",arr[i]);
}
return 0;
}

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