Test results - Codility

Tasks Details

easy

1. PermMissingElem

Find the missing element in a given permutation.

Task Score

100%

Correctness

100%

Performance

100%

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] = 5

the 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)].

Solution

Programming language used Java 8

Time spent on task 15 minutes

Notes

not defined yet

Task timeline

Code: 13:36:13 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: 13:36:52 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) {
    }
}

Code: 13:37:09 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) {
        int answer = 0;

        
    }
}

Code: 13:37:39 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;

        

        return answer;
    }
}

Code: 13:41:51 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;

        ㅗㅁ노

        return answer;
    }
}

Code: 13:42:06 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;

        HashSet<Integer> 

        return answer;
    }
}

Code: 13:42:31 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;

        HashSet<Integer> set = new HashSet<>();
        

        return answer;
    }
}

Code: 13:43:02 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;

        HashSet<Integer> set = new HashSet<>();
        for ()

        return answer;
    }
}

Code: 13:43:18 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;

        HashSet<Integer> set = new HashSet<>();
        for (int i : )

        return answer;
    }
}

Code: 13:43:29 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1)

        return answer;
    }
}

Code: 13:43:59 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2)

        return answer;
    }
}

Code: 13:44:14 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add()
        }

        return answer;
    }
}

Code: 13:44:25 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        return answer;
    }
}

Code: 13:44:38 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }
        

        return answer;
    }
}

Code: 13:44:55 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }


        return answer;
    }
}

Code: 13:45:06 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }
        

        return answer;
    }
}

Code: 13:45:16 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }


        return answer;
    }
}

Code: 13:45:27 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");
import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        

        return answer;
    }
}

Code: 13:45:38 UTC, java, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        

        return answer;
    }
}

Code: 13:45:43 UTC, java, verify, result: Failed

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        

        return answer;
    }
}

Analysis

expand all Example tests

▶

example
example test

✘

WRONG ANSWER
got 0 expected 4

0.004 s

WRONG ANSWER, got 0 expected 4

Code: 13:46:09 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for ()

        return answer;
    }
}

Code: 13:46:39 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;

        HashSet<Integer> set = new HashSet<>();
        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            
        }

        return answer;
    }
}

Code: 13:46:58 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        

        return answer;
    }
}

Code: 13:47:19 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            set.
        }

        return answer;
    }
}

Code: 13:47:49 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            set.toArray()
        }

        return answer;
    }
}

Code: 13:48:01 UTC, java, verify, result: Failed

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = set.toArray()[0];
        }

        return answer;
    }
}

Analysis

Compile error

Solution.java:18: error: incompatible types: Object cannot be converted to int
            answer = set.toArray()[0];
                                  ^
1 error

Code: 13:48:14 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = set.toArray;
        }

        return answer;
    }
}

Code: 13:48:25 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = set.toArray();
        }

        return answer;
    }
}

Code: 13:48:45 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = ((Integer[]) set.toArray());
        }

        return answer;
    }
}

Code: 13:48:58 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = ((Integer[]) set.toArray())[0];
        }

        return answer;
    }
}

Code: 13:49:07 UTC, java, verify, result: Failed

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = ((Integer[]) set.toArray())[0];
        } else {
            answer = -1;
        }

        return answer;
    }
}

Analysis

expand all Example tests

▶

example
example test

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.008 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Exception in thread "main" java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [Ljava.lang.Integer;
	at Solution.solution(Solution.java:18)
	at Exec.run(exec.java:48)
	at Exec.main(exec.java:34)

Code: 13:49:38 UTC, java, autosave

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = (set.toArray())[0];
        } else {
            answer = -1;
        }

        return answer;
    }
}

Code: 13:49:48 UTC, java, verify, result: Passed

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = (int) (set.toArray())[0];
        } else {
            answer = -1;
        }

        return answer;
    }
}

Analysis

expand all Example tests

▶

example
example test

✔

0.008 s

Code: 13:50:00 UTC, java, verify, result: Passed

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = (int) set.toArray()[0];
        } else {
            answer = -1;
        }

        return answer;
    }
}

Analysis

expand all Example tests

▶

example
example test

✔

0.008 s

Code: 13:50:08 UTC, java, verify, result: Passed

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = (int) set.toArray()[0];
        } else {
            answer = -1;
        }

        return answer;
    }
}

Analysis

expand all Example tests

▶

example
example test

✔

0.004 s

Code: 13:50:13 UTC, java, final, score: 100

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import java.util.*;

class Solution {
    public int solution(int[] A) {
        int answer = 0;
        int n = A.length;
        HashSet<Integer> set = new HashSet<>();

        for (int i=1; i<n+2; i++) {
            set.add(i);
        }

        for (int num : A) {
            set.remove(num);
        }

        if (set.size() == 1) {
            answer = (int) set.toArray()[0];
        } else {
            answer = -1;
        }

        return answer;
    }
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

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

expand all Example tests

▶

example
example test

✔

0.004 s

expand all Correctness tests

▶

empty_and_single
empty list and single element

✔

0.012 s

0.008 s

▶

missing_first_or_last
the first or the last element is missing

✔

0.012 s

0.004 s

▶

single
single element

✔

0.008 s

▶

double
two elements

✔

0.012 s

0.004 s

0.008 s

▶

simple
simple test

✔

0.008 s

expand all Performance tests

▶

medium1
medium test, length = ~10,000

✔

0.056 s

▶

medium2
medium test, length = ~10,000

✔

0.052 s

▶

large_range
range sequence, length = ~100,000

✔

0.528 s

0.264 s

▶

large1
large test, length = ~100,000

✔

0.528 s

▶

large2
large test, length = ~100,000

✔

0.316 s