Test results - Codility

Tasks Details

medium

1. LongestNonnegativeSumSlice

Given an array consisting of the integers -1, 0 and 1, find the longest slice with a non-negative sum.

Task Score

72%

Correctness

100%

Performance

45%

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].

Solution

Programming language used C#

Time spent on task 53 minutes

Notes

not defined yet

Code: 09:43:31 UTC, java, autosave

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// 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
    }
}

Code: 10:02:21 UTC, cs, autosave

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using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in C# 6.0 with .NET 4.5 (Mono)
    }
}

Code: 10:25:47 UTC, cs, autosave

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using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (A.Length - i + 1))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum > 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
    }
}

Code: 10:25:58 UTC, cs, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (A.Length - i + 1))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum > 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
            return 
    }
}

Code: 10:26:02 UTC, cs, autosave

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using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (A.Length - i + 1))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum > 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
            return maxLengthTillNow;
    }
}

Code: 10:26:03 UTC, cs, verify, result: Failed

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (A.Length - i + 1))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum > 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
            return maxLengthTillNow;
    }
}

Analysis

expand all Example tests

▶

example1
first example test

✘

WRONG ANSWER
got 6 expected 7

0.020 s

WRONG ANSWER, got 6 expected 7

▶

example2
second example test

✘

WRONG ANSWER
got 3 expected 4

0.016 s

WRONG ANSWER, got 3 expected 4

Code: 10:35:43 UTC, cs, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (i))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum >= 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
            return maxLengthTillNow;
    }
}

Code: 10:35:44 UTC, cs, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (i))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum >= 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
            return maxLengthTillNow;
    }
}

Analysis

expand all Example tests

▶

example1
first example test

✔

0.020 s

▶

example2
second example test

✔

0.016 s

Code: 10:36:18 UTC, cs, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (i))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum >= 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
            return maxLengthTillNow;
    }
}

Analysis

expand all Example tests

▶

example1
first example test

✔

0.020 s

▶

example2
second example test

✔

0.020 s

Code: 10:36:20 UTC, cs, final, score: 72

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

using System;
// you can also use other imports, for example:
// using System.Collections.Generic;

// you can write to stdout for debugging purposes, e.g.
// Console.WriteLine("this is a debug message");

class Solution {
    public int solution(int[] A) {
        int maxLengthTillNow = 0;
            int currentMaxStart = -1;
            int currentMaxEnd = -1;
            for (int i = A.Length; i >= 1; i--)
            {
                if (maxLengthTillNow < (i))
                {
                    for(int k = 0; k< (A.Length - i + 1);k++)
                    {
                        int currentSum = 0;
                        for (int j = k; j <= i+k-1; j++)
                        {
                            currentSum += A[j];
                            if (currentSum >= 0 && (j-k+1) > maxLengthTillNow)
                            {
                                maxLengthTillNow = (j - k + 1);
                                currentMaxStart = k;
                                currentMaxEnd = j;
                            }
                        }
                    }
                }
            }
            return maxLengthTillNow;
    }
}

Analysis summary

The following issues have been detected: timeout errors.

Analysis

Detected time complexity:

O(N**2)

expand all Example tests

▶

example1
first example test

✔

0.020 s

▶

example2
second example test

✔

0.020 s

expand all Correctness tests

▶

simple
small simple tests

✔

0.020 s

▶

nonnegative_sum
array with non-negative sum

✔

0.020 s

0.024 s

▶

sorted_asc
array with negative sum, sorted ascendingly

✔

0.020 s

▶

sorted_desc
array with negative sum, sorted descendingly

✔

0.016 s

▶

tricky_sequence
array in form [1]*a + [-1]*b + [1]*c, a + c = b

✔

0.020 s

0.016 s

expand all Correctness/performance tests

▶

medium_thue_morse
medium-length Thue-Morse word with 0 changed to -1

✔

0.016 s

expand all Performance tests

▶

medium_random
random array N = 2000

✔

0.016 s

0.068 s

0.036 s

▶

big_random
random array N = 10000

✘

TIMEOUT ERROR
running time: >6.00 sec., time limit: 0.10 sec.

6.000 s

TIMEOUT ERROR, running time: >6.00 sec., time limit: 0.10 sec.

6.000 s

TIMEOUT ERROR, running time: >6.00 sec., time limit: 0.10 sec.

0.024 s

▶

large_all_prefixes_positive
large array with all prefixes positive

✔

0.028 s

0.036 s

▶

max_random
random array N = 100000

✘

TIMEOUT ERROR
running time: 0.53 sec., time limit: 0.22 sec.

0.036 s

0.532 s

TIMEOUT ERROR, running time: 0.53 sec., time limit: 0.22 sec.

0.036 s

▶

max_fibonacci
array of fibonacci words N = 100000

✘

TIMEOUT ERROR
running time: >6.00 sec., time limit: 0.22 sec.

6.000 s

TIMEOUT ERROR, running time: >6.00 sec., time limit: 0.22 sec.