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 3 minutes
Notes
not defined yet
Task timeline
Code: 09:43:54 UTC,
java,
autosave
Code: 09:44:36 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");
class Solution {
public int solution(int[] A) {
HashMap<Integer, Boolean> map = new HashMap<>();
// write your code in Java SE 8
}
}
Analysis
Compile error
Solution.java:11: error: missing return statement
}
^
1 error
Code: 09:45:01 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");
class Solution {
public int solution(int[] A) {
HashMap<Integer, Boolean> map = new HashMap<>();
for(int i=0; i<A.length; i++){
}
// write your code in Java SE 8
}
}
Code: 09:45:48 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");
class Solution {
public int solution(int[] A) {
HashMap<Integer, Boolean> map = new HashMap<>();
for(int i=0; i<A.length; i++){
map.computeIfAbsent("3", val -> "THREE");
}
// write your code in Java SE 8
}
}
Code: 09:46:01 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");
class Solution {
public int solution(int[] A) {
HashMap<Integer, Boolean> map = new HashMap<>();
for(int i=0; i<A.length; i++){
map.computeIfAbsent(A[i], val -> "THREE");
}
// write your code in Java SE 8
}
}
Code: 09:46:07 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");
class Solution {
public int solution(int[] A) {
HashMap<Integer, Boolean> map = new HashMap<>();
for(int i=0; i<A.length; i++){
map.computeIfAbsent(A[i], val -> true);
}
// write your code in Java SE 8
}
}
Analysis
Compile error
Solution.java:15: error: missing return statement
}
^
1 error
Code: 09:46:31 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");
class Solution {
public int solution(int[] A) {
HashMap<Integer, Boolean> map = new HashMap<>();
for(int i=0; i<A.length; i++){
map.computeIfAbsent(A[i], val -> true);
}
// write your code in Java SE 8
return map.size()
}
}
Code: 09:46:32 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");
class Solution {
public int solution(int[] A) {
HashMap<Integer, Boolean> map = new HashMap<>();
for(int i=0; i<A.length; i++){
map.computeIfAbsent(A[i], val -> true);
}
// write your code in Java SE 8
return map.size();
}
}
Analysis
Code: 09:46:44 UTC,
java,
autosave
Code: 09:46:44 UTC,
java,
verify,
result: Passed
Analysis
Code: 09:46:48 UTC,
java,
final,
score:
100
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N*log(N)) or O(N)
expand all
Correctness tests
1.
0.008 s
OK
1.
0.084 s
OK
2.
0.084 s
OK
1.
0.084 s
OK
1.
0.084 s
OK
1.
0.084 s
OK
1.
0.084 s
OK
1.
0.084 s
OK
1.
0.088 s
OK
1.
0.088 s
OK