Tasks Details
medium
Find the smallest positive integer that does not occur in a given sequence.
Task Score
100%
Correctness
100%
Performance
100%
This is a demo task.
Write a function:
class Solution { public int solution(int[] A); }
that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.
For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.
Given A = [1, 2, 3], the function should return 4.
Given A = [−1, −3], the function should return 1.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [1..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 1 minutes
Notes
not defined yet
Task timeline
Code: 11:55:12 UTC,
java,
autosave
Code: 11:55:20 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) {
// write your code in Java SE 8
int result = 1;
Map<Integer, Boolean> map = new HashMap<>();
for (int a : A) {
if (a > 0)
map.put(a, true);
}
for(int i = 0; i < map.keySet().size(); i++){
if(!map.containsKey(result)){
return result;
}
result ++;
}
return result;
}
}
Analysis
Compile error
Solution.java:14: error: cannot find symbol
Map<Integer, Boolean> map = new HashMap<>();
^
symbol: class Map
location: class Solution
Solution.java:14: error: cannot find symbol
Map<Integer, Boolean> map = new HashMap<>();
^
symbol: class HashMap
location: class Solution
2 errors
Code: 11:55:29 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");
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
int result = 1;
Map<Integer, Boolean> map = new HashMap<>();
for (int a : A) {
if (a > 0)
map.put(a, true);
}
for(int i = 0; i < map.keySet().size(); i++){
if(!map.containsKey(result)){
return result;
}
result ++;
}
return result;
}
}
Analysis
Code: 11:55:33 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");
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
int result = 1;
Map<Integer, Boolean> map = new HashMap<>();
for (int a : A) {
if (a > 0)
map.put(a, true);
}
for(int i = 0; i < map.keySet().size(); i++){
if(!map.containsKey(result)){
return result;
}
result ++;
}
return result;
}
}
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N) or O(N * log(N))
expand all
Correctness tests
1.
0.008 s
OK
2.
0.004 s
OK
3.
0.008 s
OK
4.
0.004 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
3.
0.008 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
1.
0.008 s
OK
expand all
Performance tests
1.
0.032 s
OK
2.
0.028 s
OK
3.
0.040 s
OK
1.
0.384 s
OK
1.
0.508 s
OK
2.
0.456 s
OK
1.
0.276 s
OK