# Very cool numbers | practice problem solution hakerearth

**Program:-**

For a number X, let its “Coolness” be defined as the number of “101”s occurring in its binary representation. For example, the number 21 has Coolness 2, since its binary representation is 10101_{2}, and the string “101” occurs twice in this representation.

A number is defined as Very Cool if its Coolness is greater than or equal to K. Please, output the number of Very Cool integers between 1 and R.

Input:

The first line contains an integer T, the number of test cases.

The next T lines contains two space-separated integers, R and K.

Output:

Output T lines, the answer for each test case.

Constraints:

1<=T<=100

1<=R<=10^{5}

1<=K<=100

Time Limit:5.0 sec(s) for each input file.

Memory Limit:256 MB

Source Limit:

**Solution:-**

#include<stdio.h>

int very_cool(int n,int k) // funtion definition

{

long long int a[1000000],i=0,j;

int sum=0;

while(n>0)

{

a[i]=n%2;

n=n/2;

i++;

}

for( j=i–1;j>=2;j–)

{

if(a[j]==1&&a[j–1]==0&&a[j–2]==1)

sum++;

}

if(sum>=k)

return 1;

else

return 0;

}

void main()

{

int t,r,k,s,total_no=0;

scanf(“%d”,&t);

for(int i=0;i<t;i++)

{

scanf(“%d%d”,&r,&k);

for(int j=5;j<=r;j++)

{

s=very_cool(j,k); // function calling

total_no=total_no+s;

}

printf(“%dn”,total_no);

total_no=0;

}

}

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Good job sir 👍

Good one