Tasks Details
medium
Calculate the number of elements of an array that are not divisors of each element.
Task Score
100%
Correctness
100%
Performance
100%
You are given an array A consisting of N integers.
For each number A[i] such that 0 ≤ i < N, we want to count the number of elements of the array that are not the divisors of A[i]. We say that these elements are non-divisors.
For example, consider integer N = 5 and array A such that:
A[0] = 3 A[1] = 1 A[2] = 2 A[3] = 3 A[4] = 6For the following elements:
- A[0] = 3, the non-divisors are: 2, 6,
- A[1] = 1, the non-divisors are: 3, 2, 3, 6,
- A[2] = 2, the non-divisors are: 3, 3, 6,
- A[3] = 3, the non-divisors are: 2, 6,
- A[4] = 6, there aren't any non-divisors.
Write a function:
class Solution { public int[] solution(int[] A); }
that, given an array A consisting of N integers, returns a sequence of integers representing the amount of non-divisors.
Result array should be returned as an array of integers.
For example, given:
A[0] = 3 A[1] = 1 A[2] = 2 A[3] = 3 A[4] = 6the function should return [2, 4, 3, 2, 0], as explained above.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [1..50,000];
- each element of array A is an integer within the range [1..2 * N].
Copyright 2009–2025 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Java 21
Time spent on task 10 minutes
Notes
not defined yet
Code: 07:43:15 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
import java.util.*;
// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int[] solution(int[] A) {
Map<Integer,List<Integer>> divisorsOf = new HashMap<Integer,List<Integer>>();
Map<Integer,Integer> countOf = new HashMap<Integer,Integer>();
// calc counts and divisors
final int N = A.length;
for( int a : A ) {
Integer newCount = 1;
if( countOf.containsKey( a ) ) {
newCount = countOf.get( a ) + 1;
} else {
// Calc divisors only once
List<Integer> divisors = new ArrayList<Integer>();
final int sqrtA = (int)Math.sqrt(a);
for( int i = 1; i <= sqrtA; ++i ) {
if( 0 == a%i ) {
divisors.add( i );
if( i * i != a ) divisors.add( a/i ); // count it once
}
}
divisorsOf.put( a, divisors );
}
countOf.put( a, newCount );
}
List<Integer> result = new ArrayList<Integer>();
for( int a : A ) {
int nNonDivisors = N;
for( int d : divisorsOf.get( a ) ) {
nNonDivisors -= countOf.get( d );
}
result.add( nNonDivisors );
}
return toIntArray( result );
}
private int[] toIntArray( List<Integer> list ) {
int[] result = new int[ list.size() ];
for( int i = 0; i < result.length; ++i ) {
result[i] = list.get( i );
}
return result;
}
}
Analysis
expand all
User tests
1.
1.248 s
OK
function result: [0]
function result: [0]
1.
1.152 s
OK
function result: [3, 2, 1, 0]
function result: [3, 2, 1, 0]
User test case 1:
None
User test case 2:
None
Code: 07:44:31 UTC,
java,
verify,
result: Passed
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455
// you can also use imports, for example:
import java.util.*;
// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int[] solution(int[] A) {
Map<Integer,List<Integer>> divisorsOf = new HashMap<Integer,List<Integer>>();
Map<Integer,Integer> countOf = new HashMap<Integer,Integer>();
// calc counts and divisors
final int N = A.length;
for( int a : A ) {
Integer newCount = 1;
if( countOf.containsKey( a ) ) {
newCount = countOf.get( a ) + 1;
} else {
// Calc divisors only once
List<Integer> divisors = new ArrayList<Integer>();
final int sqrtA = (int)Math.sqrt(a);
for( int i = 1; i <= sqrtA; ++i ) {
if( 0 == a%i ) {
divisors.add( i );
if( i * i != a ) divisors.add( a/i ); // count it once
}
}
divisorsOf.put( a, divisors );
}
countOf.put( a, newCount );
}
System.out.println(countOf);
System.out.println(divisorsOf);
List<Integer> result = new ArrayList<Integer>();
for( int a : A ) {
int nNonDivisors = N;
for( int d : divisorsOf.get( a ) ) {
nNonDivisors -= countOf.get( d );
}
result.add( nNonDivisors );
}
return toIntArray( result );
}
private int[] toIntArray( List<Integer> list ) {
int[] result = new int[ list.size() ];
for( int i = 0; i < result.length; ++i ) {
result[i] = list.get( i );
}
return result;
}
}
Analysis
expand all
Example tests
1.
1.288 s
OK
stdout:
WARNING: producing output may seriously slow down your code!
{1=1, 2=1, 3=2, 6=1}
{1=[1], 2=[1, 2], 3=[1, 3], 6=[1, 6, 2, 3]}
expand all
User tests
1.
1.268 s
OK
function result: [0]
function result: [0]
stdout:
WARNING: producing output may seriously slow down your code!
{1=1}
{1=[1]}
1.
1.288 s
OK
function result: [3, 2, 1, 0]
function result: [3, 2, 1, 0]
stdout:
WARNING: producing output may seriously slow down your code!
{1=1, 2=1, 4=1, 8=1}
{1=[1], 2=[1, 2], 4=[1, 4, 2], 8=[1, 8, 2, 4]}
User test case 1:
None
User test case 2:
None
Code: 07:46:02 UTC,
java,
verify,
result: Passed
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455
// you can also use imports, for example:
import java.util.*;
// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int[] solution(int[] A) {
Map<Integer,List<Integer>> divisorsOf = new HashMap<Integer,List<Integer>>();
Map<Integer,Integer> countOf = new HashMap<Integer,Integer>();
// calc counts and divisors
final int N = A.length;
for( int a : A ) {
Integer newCount = 1;
if( countOf.containsKey( a ) ) {
newCount = countOf.get( a ) + 1;
} else {
// Calc divisors only once
List<Integer> divisors = new ArrayList<Integer>();
final int sqrtA = (int)Math.sqrt(a);
for( int i = 1; i <= sqrtA; ++i ) {
if( 0 == a%i ) {
divisors.add( i );
if( i * i != a ) divisors.add( a/i ); // count it once
}
}
divisorsOf.put( a, divisors );
}
countOf.put( a, newCount );
}
System.out.println(countOf);
System.out.println(divisorsOf);
List<Integer> result = new ArrayList<Integer>();
for( int a : A ) {
int nNonDivisors = N;
for( int d : divisorsOf.get( a ) ) {
nNonDivisors -= countOf.get( d );
}
result.add( nNonDivisors );
}
return toIntArray( result );
}
private int[] toIntArray( List<Integer> list ) {
int[] result = new int[ list.size() ];
for( int i = 0; i < result.length; ++i ) {
result[i] = list.get( i );
}
return result;
}
}
Analysis
expand all
Example tests
1.
1.264 s
OK
stdout:
WARNING: producing output may seriously slow down your code!
{1=1, 2=1, 3=2, 6=1}
{1=[1], 2=[1, 2], 3=[1, 3], 6=[1, 6, 2, 3]}
expand all
User tests
1.
1.292 s
OK
function result: [0]
function result: [0]
stdout:
WARNING: producing output may seriously slow down your code!
{1=1}
{1=[1]}
1.
1.276 s
OK
function result: [3, 2, 1, 0]
function result: [3, 2, 1, 0]
stdout:
WARNING: producing output may seriously slow down your code!
{1=1, 2=1, 4=1, 8=1}
{1=[1], 2=[1, 2], 4=[1, 4, 2], 8=[1, 8, 2, 4]}
1.
1.268 s
RUNTIME ERROR,
tested program terminated unexpectedly
stdout:
{1=1, 2=1, 50=1, 3=1, 4=1, 5=1, 120=1, 12=1}
{1=[1], 2=[1, 2], 50=[1, 50, 2, 25, 5, 10], 3=[1, 3], 4=[1, 4, 2], 5=[1, 5], 120=[1, 120, 2, 60, 3, 40, 4, 30, 5, 24, 6, 20, 8, 15, 10, 12], 12=[1, 12, 2, 6, 3, 4]}
Exception in thread "main" java.lang.NullPointerException
at Solution.solution(Solution.java:40)
at wrapper.run(wrapper.java:28)
at wrapper.main(wrapper.java:21)
1.
1.272 s
RUNTIME ERROR,
tested program terminated unexpectedly
stdout:
{2=1, 4=1, 8=1, 12=1}
{2=[1, 2], 4=[1, 4, 2], 8=[1, 8, 2, 4], 12=[1, 12, 2, 6, 3, 4]}
Exception in thread "main" java.lang.NullPointerException
at Solution.solution(Solution.java:40)
at wrapper.run(wrapper.java:28)
at wrapper.main(wrapper.java:21)
User test case 1:
None
User test case 2:
None
User test case 3:
None
User test case 4:
None
Code: 07:49:05 UTC,
java,
verify,
result: Failed
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556
// you can also use imports, for example:
import java.util.*;
// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int[] solution(int[] A) {
Map<Integer,List<Integer>> divisorsOf = new HashMap<Integer,List<Integer>>();
Map<Integer,Integer> countOf = new HashMap<Integer,Integer>();
// calc counts and divisors
final int N = A.length;
for( int a : A ) {
Integer newCount = 1;
if( countOf.containsKey( a ) ) {
newCount = countOf.get( a ) + 1;
} else {
// Calc divisors only once
List<Integer> divisors = new ArrayList<Integer>();
final int sqrtA = (int)Math.sqrt(a);
for( int i = 1; i <= sqrtA; ++i ) {
if( 0 == a%i ) {
divisors.add( i );
if( i * i != a ) divisors.add( a/i ); // count it once
}
}
divisorsOf.put( a, divisors );
}
countOf.put( a, newCount );
}
System.out.println(countOf);
System.out.println(divisorsOf);
List<Integer> result = new ArrayList<Integer>();
for( int a : A ) {
int nNonDivisors = N;
for( int d : divisorsOf.get( a ) ) {
anyD = countOf.get( d );
if( anyD != null ) nNonDivisors -= anyD;
}
result.add( nNonDivisors );
}
return toIntArray( result );
}
private int[] toIntArray( List<Integer> list ) {
int[] result = new int[ list.size() ];
for( int i = 0; i < result.length; ++i ) {
result[i] = list.get( i );
}
return result;
}
}
Analysis
Compile error
Solution.java:40: error: cannot find symbol
anyD = countOf.get( d );
^
symbol: variable anyD
location: class Solution
Solution.java:41: error: cannot find symbol
if( anyD != null ) nNonDivisors -= anyD;
^
symbol: variable anyD
location: class Solution
Solution.java:41: error: cannot find symbol
if( anyD != null ) nNonDivisors -= anyD;
^
symbol: variable anyD
location: class Solution
3 errors
Code: 07:50:57 UTC,
java,
verify,
result: Passed
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556
// you can also use imports, for example:
import java.util.*;
// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int[] solution(int[] A) {
Map<Integer,List<Integer>> divisorsOf = new HashMap<Integer,List<Integer>>();
Map<Integer,Integer> countOf = new HashMap<Integer,Integer>();
// calc counts and divisors
final int N = A.length;
for( int a : A ) {
Integer newCount = 1;
if( countOf.containsKey( a ) ) {
newCount = countOf.get( a ) + 1;
} else {
// Calc divisors only once
List<Integer> divisors = new ArrayList<Integer>();
final int sqrtA = (int)Math.sqrt(a);
for( int i = 1; i <= sqrtA; ++i ) {
if( 0 == a%i ) {
divisors.add( i );
if( i * i != a ) divisors.add( a/i ); // count it once
}
}
divisorsOf.put( a, divisors );
}
countOf.put( a, newCount );
}
System.out.println(countOf);
System.out.println(divisorsOf);
List<Integer> result = new ArrayList<Integer>();
for( int a : A ) {
int nNonDivisors = N;
for( int d : divisorsOf.get( a ) ) {
Integer anyD = countOf.get( d );
if( anyD != null ) nNonDivisors -= anyD;
}
result.add( nNonDivisors );
}
return toIntArray( result );
}
private int[] toIntArray( List<Integer> list ) {
int[] result = new int[ list.size() ];
for( int i = 0; i < result.length; ++i ) {
result[i] = list.get( i );
}
return result;
}
}
Analysis
expand all
Example tests
1.
1.208 s
OK
stdout:
WARNING: producing output may seriously slow down your code!
{1=1, 2=1, 3=2, 6=1}
{1=[1], 2=[1, 2], 3=[1, 3], 6=[1, 6, 2, 3]}
expand all
User tests
1.
1.300 s
OK
function result: [0]
function result: [0]
stdout:
WARNING: producing output may seriously slow down your code!
{1=1}
{1=[1]}
1.
1.484 s
OK
function result: [3, 2, 1, 0]
function result: [3, 2, 1, 0]
stdout:
WARNING: producing output may seriously slow down your code!
{1=1, 2=1, 4=1, 8=1}
{1=[1], 2=[1, 2], 4=[1, 4, 2], 8=[1, 8, 2, 4]}
1.
1.576 s
OK
function result: [7, 6, 6, 5, 3, 1, 6, 4]
function result: [7, 6, 6, 5, 3, 1, 6, 4]
stdout:
WARNING: producing output may seriously slow down your code!
{1=1, 2=1, 50=1, 3=1, 4=1, 5=1, 120=1, 12=1}
{1=[1], 2=[1, 2], 50=[1, 50, 2, 25, 5, 10], 3=[1, 3], 4=[1, 4, 2], 5=[1, 5], 120=[1, 120, 2, 60, 3, 40, 4, 30, 5, 24, 6, 20, 8, 15, 10, 12], 12=[1, 12, 2, 6, 3, 4]}
1.
1.452 s
OK
function result: [2, 1, 3, 4, 4, 1]
function result: [2, 1, 3, 4, 4, 1]
stdout:
WARNING: producing output may seriously slow down your code!
{2=2, 4=1, 8=2, 12=1}
{2=[1, 2], 4=[1, 4, 2], 8=[1, 8, 2, 4], 12=[1, 12, 2, 6, 3, 4]}
User test case 1:
None
User test case 2:
None
User test case 3:
None
User test case 4:
None
Code: 07:51:40 UTC,
java,
verify,
result: Passed
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556
// you can also use imports, for example:
import java.util.*;
// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int[] solution(int[] A) {
Map<Integer,List<Integer>> divisorsOf = new HashMap<Integer,List<Integer>>();
Map<Integer,Integer> countOf = new HashMap<Integer,Integer>();
// calc counts and divisors
final int N = A.length;
for( int a : A ) {
Integer newCount = 1;
if( countOf.containsKey( a ) ) {
newCount = countOf.get( a ) + 1;
} else {
// Calc divisors only once
List<Integer> divisors = new ArrayList<Integer>();
final int sqrtA = (int)Math.sqrt(a);
for( int i = 1; i <= sqrtA; ++i ) {
if( 0 == a%i ) {
divisors.add( i );
if( i * i != a ) divisors.add( a/i ); // count it once
}
}
divisorsOf.put( a, divisors );
}
countOf.put( a, newCount );
}
// System.out.println(countOf);
// System.out.println(divisorsOf);
List<Integer> result = new ArrayList<Integer>();
for( int a : A ) {
int nNonDivisors = N;
for( int d : divisorsOf.get( a ) ) {
Integer anyD = countOf.get( d );
if( anyD != null ) nNonDivisors -= anyD;
}
result.add( nNonDivisors );
}
return toIntArray( result );
}
private int[] toIntArray( List<Integer> list ) {
int[] result = new int[ list.size() ];
for( int i = 0; i < result.length; ++i ) {
result[i] = list.get( i );
}
return result;
}
}
Analysis
expand all
User tests
1.
1.564 s
OK
function result: [0]
function result: [0]
1.
1.524 s
OK
function result: [3, 2, 1, 0]
function result: [3, 2, 1, 0]
1.
1.492 s
OK
function result: [7, 6, 6, 5, 3, 1, 6, 4]
function result: [7, 6, 6, 5, 3, 1, 6, 4]
1.
1.516 s
OK
function result: [2, 1, 3, 4, 4, 1]
function result: [2, 1, 3, 4, 4, 1]
User test case 1:
None
User test case 2:
None
User test case 3:
None
User test case 4:
None
Code: 07:51:58 UTC,
java,
final,
score:
100
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556
// you can also use imports, for example:
import java.util.*;
// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int[] solution(int[] A) {
Map<Integer,List<Integer>> divisorsOf = new HashMap<Integer,List<Integer>>();
Map<Integer,Integer> countOf = new HashMap<Integer,Integer>();
// calc counts and divisors
final int N = A.length;
for( int a : A ) {
Integer newCount = 1;
if( countOf.containsKey( a ) ) {
newCount = countOf.get( a ) + 1;
} else {
// Calc divisors only once
List<Integer> divisors = new ArrayList<Integer>();
final int sqrtA = (int)Math.sqrt(a);
for( int i = 1; i <= sqrtA; ++i ) {
if( 0 == a%i ) {
divisors.add( i );
if( i * i != a ) divisors.add( a/i ); // count it once
}
}
divisorsOf.put( a, divisors );
}
countOf.put( a, newCount );
}
// System.out.println(countOf);
// System.out.println(divisorsOf);
List<Integer> result = new ArrayList<Integer>();
for( int a : A ) {
int nNonDivisors = N;
for( int d : divisorsOf.get( a ) ) {
Integer anyD = countOf.get( d );
if( anyD != null ) nNonDivisors -= anyD;
}
result.add( nNonDivisors );
}
return toIntArray( result );
}
private int[] toIntArray( List<Integer> list ) {
int[] result = new int[ list.size() ];
for( int i = 0; i < result.length; ++i ) {
result[i] = list.get( i );
}
return result;
}
}
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N * log(N))