Tasks Details
easy
Find the missing element in a given permutation.
Task Score
80%
Correctness
100%
Performance
60%
An array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.
Your goal is to find that missing element.
Write a function:
class Solution { public int solution(int[] A); }
that, given an array A, returns the value of the missing element.
For example, given array A such that:
A[0] = 2 A[1] = 3 A[2] = 1 A[3] = 5the function should return 4, as it is the missing element.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..100,000];
- the elements of A are all distinct;
- each element of array A is an integer within the range [1..(N + 1)].
Copyright 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used C#
Time spent on task 3 minutes
Notes
not defined yet
Task timeline
Code: 16:06:47 UTC,
cs,
verify,
result: Failed
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)
{
long total = ((2+A.Length)*(A.Length+1)/2;
long sum=0L;
for(int i=0;i<A.Length;i++)
{
sum+=A[i];
}
return (int)(total-sum);
}
}
Analysis
Compile error
Compilation failed: 1 error(s), 0 warnings Solution.cs(12,49): error CS1026: Unexpected symbol `;', expecting `)'
Code: 16:07:26 UTC,
cs,
verify,
result: Passed
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)
{
long total = ((2+A.Length)*(A.Length+1)/2);
long sum=0L;
for(int i=0;i<A.Length;i++)
{
sum+=A[i];
}
return (int)(total-sum);
}
}
Analysis
Code: 16:07:31 UTC,
cs,
verify,
result: Passed
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)
{
long total = ((2+A.Length)*(A.Length+1)/2);
long sum=0L;
for(int i=0;i<A.Length;i++)
{
sum+=A[i];
}
return (int)(total-sum);
}
}
Analysis
Code: 16:07:34 UTC,
cs,
final,
score:
80
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)
{
long total = ((2+A.Length)*(A.Length+1)/2);
long sum=0L;
for(int i=0;i<A.Length;i++)
{
sum+=A[i];
}
return (int)(total-sum);
}
}
Analysis summary
The following issues have been detected: wrong answers.
Analysis
Detected time complexity:
O(N) or O(N * log(N))
expand all
Correctness tests
1.
0.060 s
OK
2.
0.060 s
OK
1.
0.061 s
OK
2.
0.061 s
OK
1.
0.060 s
OK
2.
0.061 s
OK
1.
0.061 s
OK
2.
0.061 s
OK
3.
0.061 s
OK
1.
0.060 s
OK
expand all
Performance tests
1.
0.065 s
OK
1.
0.064 s
OK
1.
0.096 s
OK
2.
0.079 s
WRONG ANSWER,
got -2147483647 expected 1
3.
0.082 s
WRONG ANSWER,
got -2147471303 expected 12345
1.
0.097 s
OK
1.
0.083 s
WRONG ANSWER,
got -2147473647 expected 10001