Tasks Details
easy
Rotate an array to the right by a given number of steps.
Task Score
100%
Correctness
100%
Performance
Not assessed
An array A consisting of N integers is given. Rotation of the array means that each element is shifted right by one index, and the last element of the array is moved to the first place. For example, the rotation of array A = [3, 8, 9, 7, 6] is [6, 3, 8, 9, 7] (elements are shifted right by one index and 6 is moved to the first place).
The goal is to rotate array A K times; that is, each element of A will be shifted to the right K times.
Write a function:
class Solution { public int[] solution(int[] A, int K); }
that, given an array A consisting of N integers and an integer K, returns the array A rotated K times.
For example, given
A = [3, 8, 9, 7, 6] K = 3the function should return [9, 7, 6, 3, 8]. Three rotations were made:
[3, 8, 9, 7, 6] -> [6, 3, 8, 9, 7] [6, 3, 8, 9, 7] -> [7, 6, 3, 8, 9] [7, 6, 3, 8, 9] -> [9, 7, 6, 3, 8]For another example, given
A = [0, 0, 0] K = 1the function should return [0, 0, 0]
Given
A = [1, 2, 3, 4] K = 4the function should return [1, 2, 3, 4]
Assume that:
- N and K are integers within the range [0..100];
- each element of array A is an integer within the range [−1,000..1,000].
In your solution, focus on correctness. The performance of your solution will not be the focus of the assessment.
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: 08:39:31 UTC,
java,
autosave
Code: 08:39:35 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, int K) {
int N = A.length;
int[] B = new int[N];
if (N > 0 && K > 0) {
ArrayList<Integer> arrayB = new ArrayList<Integer>();
for (int i = 0; i < N; i++) {
arrayB.add(A[i]);
}
for (int j = 0; j < K; j++) {
arrayB.add(0, arrayB.get(arrayB.size() - 1));
arrayB.remove(arrayB.size() - 1);
}
for (int k = 0; k < arrayB.size(); k++) {
B[k] = (int) arrayB.get(k);
}
} else {
B = A;
}
return B;
}
}
Analysis
Compile error
Solution.java:13: error: cannot find symbol
ArrayList<Integer> arrayB = new ArrayList<Integer>();
^
symbol: class ArrayList
location: class Solution
Solution.java:13: error: cannot find symbol
ArrayList<Integer> arrayB = new ArrayList<Integer>();
^
symbol: class ArrayList
location: class Solution
2 errors
Code: 08:40:01 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
import java.util.ArrayList;
// 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, int K) {
int N = A.length;
int[] B = new int[N];
if (N > 0 && K > 0) {
ArrayList<Integer> arrayB = new ArrayList<Integer>();
for (int i = 0; i < N; i++) {
arrayB.add(A[i]);
}
for (int j = 0; j < K; j++) {
arrayB.add(0, arrayB.get(arrayB.size() - 1));
arrayB.remove(arrayB.size() - 1);
}
for (int k = 0; k < arrayB.size(); k++) {
B[k] = (int) arrayB.get(k);
}
} else {
B = A;
}
return B;
}
}
Code: 08:40:05 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.ArrayList;
// 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, int K) {
int N = A.length;
int[] B = new int[N];
if (N > 0 && K > 0) {
ArrayList<Integer> arrayB = new ArrayList<Integer>();
for (int i = 0; i < N; i++) {
arrayB.add(A[i]);
}
for (int j = 0; j < K; j++) {
arrayB.add(0, arrayB.get(arrayB.size() - 1));
arrayB.remove(arrayB.size() - 1);
}
for (int k = 0; k < arrayB.size(); k++) {
B[k] = (int) arrayB.get(k);
}
} else {
B = A;
}
return B;
}
}
Analysis
Code: 08:40:12 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.ArrayList;
// 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, int K) {
int N = A.length;
int[] B = new int[N];
if (N > 0 && K > 0) {
ArrayList<Integer> arrayB = new ArrayList<Integer>();
for (int i = 0; i < N; i++) {
arrayB.add(A[i]);
}
for (int j = 0; j < K; j++) {
arrayB.add(0, arrayB.get(arrayB.size() - 1));
arrayB.remove(arrayB.size() - 1);
}
for (int k = 0; k < arrayB.size(); k++) {
B[k] = (int) arrayB.get(k);
}
} else {
B = A;
}
return B;
}
}
Analysis
Code: 08:40:17 UTC,
java,
final,
score:
100
// you can also use imports, for example:
// import java.util.*;
import java.util.ArrayList;
// 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, int K) {
int N = A.length;
int[] B = new int[N];
if (N > 0 && K > 0) {
ArrayList<Integer> arrayB = new ArrayList<Integer>();
for (int i = 0; i < N; i++) {
arrayB.add(A[i]);
}
for (int j = 0; j < K; j++) {
arrayB.add(0, arrayB.get(arrayB.size() - 1));
arrayB.remove(arrayB.size() - 1);
}
for (int k = 0; k < arrayB.size(); k++) {
B[k] = (int) arrayB.get(k);
}
} else {
B = A;
}
return B;
}
}
Analysis summary
The solution obtained perfect score.
Analysis
expand all
Correctness tests
1.
0.008 s
OK
2.
0.008 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
3.
0.012 s
OK
1.
0.008 s
OK
2.
0.004 s
OK
1.
0.008 s
OK
2.
0.008 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
3.
0.012 s
OK
4.
0.008 s
OK
5.
0.008 s
OK
6.
0.008 s
OK
7.
0.008 s
OK
8.
0.004 s
OK
9.
0.012 s
OK
10.
0.008 s
OK
11.
0.008 s
OK
12.
0.008 s
OK
13.
0.008 s
OK
14.
0.008 s
OK
15.
0.012 s
OK
1.
0.008 s
OK
2.
0.012 s
OK
1.
0.012 s
OK
2.
0.012 s
OK
3.
0.008 s
OK
4.
0.008 s
OK