Test results - Codility

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] = 1

the 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].

Solution

Programming language used C#

Time spent on task 12 minutes

Notes

not defined yet

Code: 09:45:14 UTC, cs, verify, result: Failed

show code in pop-up

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using System;
using System.Collections.Generic;

class Solution {
    public int solution(int[] A) {
        
        List<int> li = new List<int>();        
        
        for(int i = 0; i < A.Length; i++)
        {
            bool isFound = false;
            
            for(int j = 0; j < li.Count; j++)
            {
                if(A[i] == li[j])
                {
                    found = true;
                    break;
                }
            }
            
            if(!found) li.Add(A[i]);
        }
        
        return li.Count;
    }
}

Analysis

Compile error

Compilation failed: 2 error(s), 0 warnings
Solution.cs(17,21): error CS0103: The name `found' does not exist in the current context
Solution.cs(22,17): error CS0103: The name `found' does not exist in the current context

Code: 09:46:32 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

using System;
using System.Collections.Generic;

class Solution {
    public int solution(int[] A) {
        
        List<int> li = new List<int>();
        
        for(int i = 0; i < A.Length; i++)
        {
            bool found = false;
            
            for(int j = 0; j < li.Count; j++)
            {
                if(A[i] == li[j])
                {
                    found = true;
                    break;
                }
            }
            
            if(!found) li.Add(A[i]);
        }
        
        return li.Count;
    }
}

Analysis

expand all Example tests

▶

example1
example test, positive answer

✔

0.033 s

Code: 09:51:45 UTC, cs, verify, result: Failed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11

using System;
using System.Collections.Generic;

class Solution {
    public int solution(int[] A) {
        
        int [] newA = A.Distinct().ToArray();
        if (A.Length <=0) return 0;
        else return newA.Length;
    }
}

Analysis

Compile error

Compilation failed: 1 error(s), 0 warnings
Solution.cs(7,25): error CS1061: Type `int[]' does not contain a definition for `Distinct' and no extension method `Distinct' of type `int[]' could be found. Are you missing `System.Linq' using directive?
/opt/lang/mono/lib/mono/4.5/mscorlib.dll (Location of the symbol related to previous error)

Code: 09:53:36 UTC, cs, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12

using System;
using System.Collections.Generic;
using System.Linq;

class Solution {
    public int solution(int[] A) {
        
        int [] newA = A.Distinct().ToArray();
        if (A.Length <=0) return 0;
        else return newA.Length;
    }
}

Analysis

expand all Example tests

▶

example1
example test, positive answer

✔

0.063 s

Code: 09:53:45 UTC, cs, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11

using System;
using System.Linq;

class Solution {
    public int solution(int[] A) {
        
        int [] newA = A.Distinct().ToArray();
        if (A.Length <=0) return 0;
        else return newA.Length;
    }
}

Analysis

expand all Example tests

▶

example1
example test, positive answer

✔

0.062 s

Code: 09:55:14 UTC, cs, verify, result: Failed

show code in pop-up

1 2 3 4 5 6 7 8 9

using System;
using System.Linq;

class Solution {
    public int solution(int[] A) {
        int [] array = A.Distinct().ToArray();
        else return array.Length;
    }
}

Analysis

Compile error

Compilation failed: 1 error(s), 0 warnings
Solution.cs(7,8): error CS1525: Unexpected symbol `else'

Code: 09:55:26 UTC, cs, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9

using System;
using System.Linq;

class Solution {
    public int solution(int[] A) {
        int [] array = A.Distinct().ToArray();
        return array.Length;
    }
}

Analysis

expand all Example tests

▶

example1
example test, positive answer

✔

0.038 s

Code: 09:55:33 UTC, cs, verify, result: Passed

show code in pop-up

1 2 3 4 5 6 7 8 9

using System;
using System.Linq;

class Solution {
    public int solution(int[] A) {
        int [] array = A.Distinct().ToArray();
        return array.Length;
    }
}

Analysis

expand all Example tests

▶

example1
example test, positive answer

✔

0.050 s

Code: 09:55:36 UTC, cs, final, score: 100

show code in pop-up

1 2 3 4 5 6 7 8 9

using System;
using System.Linq;

class Solution {
    public int solution(int[] A) {
        int [] array = A.Distinct().ToArray();
        return array.Length;
    }
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N*log(N)) or O(N)

expand all Example tests

▶

example1
example test, positive answer

✔

0.063 s

expand all Correctness tests

▶

extreme_empty
empty sequence

✔

0.061 s

▶

extreme_single
sequence of one element

✔

0.062 s

0.065 s

▶

extreme_two_elems
sequence of three distinct elements

✔

0.065 s

▶

extreme_one_value
sequence of 10 equal elements

✔

0.062 s

▶

extreme_negative
sequence of negative elements, length=5

✔

0.062 s

▶

extreme_big_values
sequence with big values, length=5

✔

0.062 s

▶

medium1
chaotic sequence of value sfrom [0..1K], length=100

✔

0.066 s

▶

medium2
chaotic sequence of value sfrom [0..1K], length=200

✔

0.064 s

▶

medium3
chaotic sequence of values from [0..10], length=200

✔

0.066 s

expand all Performance tests

▶

large1
chaotic sequence of values from [0..100K], length=10K

✔

0.071 s

▶

large_random1
chaotic sequence of values from [-1M..1M], length=100K

✔

0.118 s

▶

large_random2
another chaotic sequence of values from [-1M..1M], length=100K

✔

0.116 s