Tasks Details
easy
1.
Distinct
Compute number of distinct values in an array.
Task Score
100%
Correctness
100%
Performance
100%
Write a function
class Solution { public int solution(int[] A); }
that, given an array A consisting of N integers, returns the number of distinct values in array A.
For example, given array A consisting of six elements such that:
A[0] = 2 A[1] = 1 A[2] = 1 A[3] = 2 A[4] = 3 A[5] = 1the function should return 3, because there are 3 distinct values appearing in array A, namely 1, 2 and 3.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..100,000];
- each element of array A is an integer within the range [−1,000,000..1,000,000].
Copyright 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Java 8
Time spent on task 2 minutes
Notes
not defined yet
Task timeline
Code: 03:11:51 UTC,
java,
autosave
Code: 03:12:14 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Arrays;
class Solution {
public int solution(int[] A) {
return Arrays.stream(A).distinct().count();
}
}
Analysis
Compile error
Solution.java:11: error: incompatible types: possible lossy conversion from long to int
return Arrays.stream(A).distinct().count();
^
1 error
Code: 03:12:26 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Arrays;
class Solution {
public int solution(int[] A) {
return InArrays.stream(A).distinct().count();
}
}
Code: 03:12:33 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Arrays;
class Solution {
public int solution(int[] A) {
return Integer.parseInt(Arrays.stream(A).distinct().count());
}
}
Analysis
Compile error
Solution.java:11: error: incompatible types: long cannot be converted to String
return Integer.parseInt(Arrays.stream(A).distinct().count());
^
Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output
1 error
Code: 03:13:16 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Arrays;
class Solution {
public int solution(int[] A) {
return ())Arrays.stream(A).distinct().count());
}
}
Code: 03:13:22 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Arrays;
class Solution {
public int solution(int[] A) {
return (int) Arrays.stream(A).distinct().count();
}
}
Analysis
Code: 03:13:29 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Arrays;
class Solution {
public int solution(int[] A) {
return (int) Arrays.stream(A).distinct().count();
}
}
Analysis
Code: 03:13:33 UTC,
java,
final,
score:
100
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
import java.util.Arrays;
class Solution {
public int solution(int[] A) {
return (int) Arrays.stream(A).distinct().count();
}
}
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N*log(N)) or O(N)
expand all
Correctness tests
1.
0.100 s
OK
1.
0.100 s
OK
2.
0.104 s
OK
1.
0.100 s
OK
1.
0.104 s
OK
1.
0.104 s
OK
1.
0.104 s
OK
1.
0.104 s
OK
1.
0.104 s
OK
1.
0.104 s
OK