Tasks Details
medium
Given an array consisting of the integers -1, 0 and 1, find the longest slice with a non-negative sum.
Task Score
81%
Correctness
100%
Performance
63%
You are given an array A consisting of the integers −1, 0 and 1. A slice of that array is any pair of integers (P, Q) such that 0 ≤ P ≤ Q < N. Your task is to find the longest slice of A whose elements yield a non-negative sum.
Write a function:
class Solution { public int solution(int[] A); }
that, given an array A of length N, consisting only of the values −1, 0, 1, returns the length of the longest slice of A that yields a non-negative sum. If there's no such slice, your function should return 0.
For example, given A = [−1, −1, 1, −1, 1, 0, 1, −1, −1], your function should return 7, as the slice starting at the second position and ending at the eighth is the longest slice with a non-negative sum.
For another example, given A = [1, 1, −1, −1, −1, −1, −1, 1, 1] your function should return 4: both the first four elements and the last four elements of array A are longest valid slices.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [2..100,000];
- each element of array A is an integer within the range [−1..1].
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 3 minutes
Notes
not defined yet
Code: 16:55:47 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 {
int sum = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
}
int maxPossibleLength = A.length;
// Special Case:
if (sum > -1) {
return A.length;
} else {
maxPossibleLength = A.length + sum;
}
int solution = 0;
int currentSolution = 0;
for (int i = 0; i < A.length - solution; i++) {
int s = 0;
currentSolution = 0;
for (int j = i; j < i + maxPossibleLength && j < A.length; j++) {
s += A[j];
currentSolution++;
if (s > -1) {
solution = Math.max(solution, currentSolution);
}
}
}
return solution;
}
Analysis
Compile error
Solution.java:9: error: illegal start of type
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: ')' expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: illegal start of type
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: <identifier> expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: ';' expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: > expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: '(' expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: <identifier> expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: illegal start of type
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: <identifier> expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:9: error: ';' expected
for (int i = 0; i < A.length; i++) {
^
Solution.java:10: error: illegal start of type
sum += A[i];
^
Solution.java:10: error: ']' expected
sum += A[i];
^
Solution.java:10: error: illegal start of type
sum += A[i];
^
Solution.java:10: error: <identifier> expected
sum += A[i];
^
Solution.java:10: error: ';' expected
sum += A[i];
^
Solution.java:15: error: illegal start of type
if (sum > -1) {
^
Solution.java:15: error: <identifier> expected
if (sum > -1) {
^
Solution.java:15: error: ';' expected
if (sum > -1) {
^
Solution.java:15: error: illegal start of type
if (sum > -1) {
^
Solution.java:15: error: <identifier> expected
if (sum > -1) {
^
Solution.java:15: error: ';' expected
if (sum > -1) {
^
Solution.java:16: error: illegal start of type
return A.length
Code: 16:56:17 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) {
int sum = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
}
int maxPossibleLength = A.length;
// Special Case:
if (sum > -1) {
return A.length;
} else {
maxPossibleLength = A.length + sum;
}
int solution = 0;
int currentSolution = 0;
for (int i = 0; i < A.length - solution; i++) {
int s = 0;
currentSolution = 0;
for (int j = i; j < i + maxPossibleLength && j < A.length; j++) {
s += A[j];
currentSolution++;
if (s > -1) {
solution = Math.max(solution, currentSolution);
}
}
}
return solution;
}
}
Analysis
Code: 16:56:51 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) {
int sum = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
}
int maxPossibleLength = A.length;
// Special Case:
if (sum > -1) {
return A.length;
} else {
maxPossibleLength = A.length + sum;
}
int solution = 0;
int currentSolution = 0;
for (int i = 0; i < A.length - solution; i++) {
int s = 0;
currentSolution = 0;
for (int j = i; j < i + maxPossibleLength && j < A.length; j++) {
s += A[j];
currentSolution++;
if (s > -1) {
solution = Math.max(solution, currentSolution);
}
}
}
return solution;
}
}
Analysis
Code: 16:56:55 UTC,
java,
final,
score:
81
// 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 sum = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
}
int maxPossibleLength = A.length;
// Special Case:
if (sum > -1) {
return A.length;
} else {
maxPossibleLength = A.length + sum;
}
int solution = 0;
int currentSolution = 0;
for (int i = 0; i < A.length - solution; i++) {
int s = 0;
currentSolution = 0;
for (int j = i; j < i + maxPossibleLength && j < A.length; j++) {
s += A[j];
currentSolution++;
if (s > -1) {
solution = Math.max(solution, currentSolution);
}
}
}
return solution;
}
}Analysis summary
The following issues have been detected: timeout errors.
Analysis
Detected time complexity:
O(N*log(N)) or O(N) or O(N**2)
expand all
Correctness tests
1.
0.004 s
OK
2.
0.008 s
OK
3.
0.004 s
OK
4.
0.004 s
OK
1.
0.004 s
OK
2.
0.004 s
OK
1.
0.004 s
OK
1.
0.004 s
OK
1.
0.004 s
OK
2.
0.004 s
OK
expand all
Correctness/performance tests
1.
0.004 s
OK
expand all
Performance tests
1.
0.008 s
OK
2.
0.016 s
OK
3.
0.016 s
OK
1.
5.124 s
TIMEOUT ERROR,
running time: 5.12 sec., time limit: 0.43 sec.
2.
2.200 s
TIMEOUT ERROR,
running time: 2.20 sec., time limit: 0.45 sec.
3.
0.032 s
OK
1.
0.076 s
OK
2.
0.100 s
OK
3.
0.152 s
OK
1.
0.156 s
OK
2.
0.424 s
OK
3.
0.152 s
OK
max_fibonacci
array of fibonacci words N = 100000
array of fibonacci words N = 100000
✘
TIMEOUT ERROR
running time: >8.00 sec., time limit: 2.27 sec.
running time: >8.00 sec., time limit: 2.27 sec.
1.
8.000 s
TIMEOUT ERROR,
running time: >8.00 sec., time limit: 2.27 sec.