Test results - Codility

Tasks Details

easy

1. Triangle

Determine whether a triangle can be built from a given set of edges.

93%

90%

100%

An array A consisting of N integers is given. A triplet (P, Q, R) is triangular if 0 ≤ P < Q < R < N and:

A[P] + A[Q] > A[R],

A[Q] + A[R] > A[P],

A[R] + A[P] > A[Q].

For example, consider array A such that:

A[0] = 10 A[1] = 2 A[2] = 5 A[3] = 1 A[4] = 8 A[5] = 20

Triplet (0, 2, 4) is triangular.

Write a function:

class Solution { public int solution(int[] A); }

that, given an array A consisting of N integers, returns 1 if there exists a triangular triplet for this array and returns 0 otherwise.

For example, given array A such that:

A[0] = 10 A[1] = 2 A[2] = 5 A[3] = 1 A[4] = 8 A[5] = 20

the function should return 1, as explained above. Given array A such that:

A[0] = 10 A[1] = 50 A[2] = 5 A[3] = 1

the function should return 0.

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 [−2,147,483,648..2,147,483,647].

Solution

Programming language used C#

Time spent on task 2 minutes

Notes

not defined yet

Task timeline

Code: 13:06:02 UTC, cs, verify, result: Passed

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

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

// you can use Console.WriteLine 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)
        Array.Sort(A);
    if (A.Length <3) return 1;
    
    for (int i=0 ; i<A.Length-3 ; i++)
      {  if (A[i] + A[i+1] > A[i+2] ) 
                {return 1;
                break;
                }
         
      }
      return 0;
    }
}

Analysis

▶

example
example, positive answer, length=6

✔

▶

example1
example, answer is zero, length=4

✔

Code: 13:06:32 UTC, cs, verify, result: Passed

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

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

// you can use Console.WriteLine 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)
        Array.Sort(A);
    if (A.Length <3) return 1;
    
    for (int i=0 ; i<A.Length-2 ; i++)
      {  if (A[i] + A[i+1] > A[i+2] ) 
                {return 1;
                break;
                }
         
      }
      return 0;
    }
}

Analysis

▶

example
example, positive answer, length=6

✔

▶

example1
example, answer is zero, length=4

✔

Code: 13:06:49 UTC, cs, verify, result: Passed

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

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

// you can use Console.WriteLine 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)
        Array.Sort(A);
    if (A.Length <3) return 0;
    
    for (int i=0 ; i<A.Length-2 ; i++)
      {  if (A[i] + A[i+1] > A[i+2] ) 
                {return 1;
                break;
                }
         
      }
      return 0;
    }
}

Analysis

▶

example
example, positive answer, length=6

✔

▶

example1
example, answer is zero, length=4

✔

Code: 13:06:55 UTC, cs, verify, result: Passed

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

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

// you can use Console.WriteLine 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)
        Array.Sort(A);
    if (A.Length <3) return 0;
    
    for (int i=0 ; i<A.Length-2 ; i++)
      {  if (A[i] + A[i+1] > A[i+2] ) 
                {return 1;
                break;
                }
         
      }
      return 0;
    }
}

Analysis

▶

example
example, positive answer, length=6

✔

▶

example1
example, answer is zero, length=4

✔

Code: 13:07:00 UTC, cs, final, score: 93

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

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

// you can use Console.WriteLine 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)
        Array.Sort(A);
    if (A.Length <3) return 0;
    
    for (int i=0 ; i<A.Length-2 ; i++)
      {  if (A[i] + A[i+1] > A[i+2] ) 
                {return 1;
                break;
                }
         
      }
      return 0;
    }
}

Analysis summary

The following issues have been detected: wrong answers.

Analysis

Detected time complexity:

O(N*log(N))

▶

example
example, positive answer, length=6

✔

▶

example1
example, answer is zero, length=4

✔

▶

extreme_empty
empty sequence

✔

▶

extreme_single
1-element sequence

✔

▶

extreme_two_elems
2-element sequence

✔

▶

extreme_negative1
three equal negative numbers

✔

▶

extreme_arith_overflow1
overflow test, 3 MAXINTs

✘

WRONG ANSWER
got 0 expected 1

▶

extreme_arith_overflow2
overflow test, 10 and 2 MININTs

✔

▶

extreme_arith_overflow3
overflow test, 0 and 2 MAXINTs

✔

▶

medium1
chaotic sequence of values from [0..100K], length=30

✔

▶

medium2
chaotic sequence of values from [0..1K], length=50

✔

▶

medium3
chaotic sequence of values from [0..1K], length=100

✔

▶

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

✔

▶

large2
1 followed by an ascending sequence of ~50K elements from [0..100K], length=~50K

✔

▶

large_random
chaotic sequence of values from [0..1M], length=100K

✔

▶

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

✔

▶

large_negative2
chaotic sequence of negative values from [-10..-1], length=100K

✔

▶

large_negative3
sequence of -1 value, length=100K

✔