Test results - Codility

Tasks Details

easy

1. PermCheck

Check whether array A is a permutation.

Task Score

100%

Correctness

100%

Performance

100%

A non-empty array A consisting of N integers is given.

A permutation is a sequence containing each element from 1 to N once, and only once.

For example, array A such that:

A[0] = 4 A[1] = 1 A[2] = 3 A[3] = 2

is a permutation, but array A such that:

A[0] = 4 A[1] = 1 A[2] = 3

is not a permutation, because value 2 is missing.

The goal is to check whether array A is a permutation.

Write a function:

function solution(A);

that, given an array A, returns 1 if array A is a permutation and 0 if it is not.

For example, given array A such that:

A[0] = 4 A[1] = 1 A[2] = 3 A[3] = 2

the function should return 1.

Given array A such that:

A[0] = 4 A[1] = 1 A[2] = 3

the function should return 0.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [1..100,000];

each element of array A is an integer within the range [1..1,000,000,000].

Solution

Programming language used JavaScript

Time spent on task 4 minutes

Notes

not defined yet

Task timeline

Code: 16:03:14 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");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
    }
}

Code: 16:03:14 UTC, java, autosave

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1 2 3 4 5 6 7 8 9 10 11

// 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: 16:03:25 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Duplication early rejection check.
        if (array[A[i]]) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:03:38 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i]]) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:03:51 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i]] || array[A[i]]) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:04:06 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i]] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:04:07 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i]] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Analysis

expand all Example tests

▶

example1
the first example test

✘

WRONG ANSWER
got 0 expected 1

0.112 s

WRONG ANSWER, got 0 expected 1

▶

example2
the second example test

✔

0.120 s

stdout:

should not hit

Code: 16:04:28 UTC, js, verify, result: Failed

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i]] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(!!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Analysis

expand all Example tests

▶

example1
the first example test

✘

WRONG ANSWER
got 0 expected 1

0.072 s

WRONG ANSWER, got 0 expected 1

▶

example2
the second example test

✔

0.072 s

stdout:

should not hit

Code: 16:04:37 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i]] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }
console.log(array)
    for(let i = 0; i < A.length; ++i) {
        if(!!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:04:38 UTC, js, verify, result: Failed

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i]] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }
console.log(array)
    for(let i = 0; i < A.length; ++i) {
        if(!!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Analysis

expand all Example tests

▶

example1
the first example test

✘

WRONG ANSWER
got 0 expected 1

0.076 s

WRONG ANSWER, got 0 expected 1

stdout:

[ <1 empty item>, true, true, true, true ]

▶

example2
the second example test

✔

0.072 s

stdout:

should not hit

Code: 16:04:50 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i]] = true;
    }
console.log(array)
    for(let i = 0; i < A.length; ++i) {
        if(!!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:04:59 UTC, js, verify, result: Failed

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i] - 1] = true;
    }
console.log(array)
    for(let i = 0; i < A.length; ++i) {
        if(!!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Analysis

expand all Example tests

▶

example1
the first example test

✘

WRONG ANSWER
got 0 expected 1

0.076 s

WRONG ANSWER, got 0 expected 1

stdout:

[ true, true, true, true ]

▶

example2
the second example test

✔

0.076 s

stdout:

should not hit

Code: 16:05:21 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i] - 1] = true;
    }
console.log(array)
    for(let i = 0; i < A.length; ++i) {
        if(!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:05:21 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            console.log("should not hit");
            return 0;
        }
        array[A[i] - 1] = true;
    }
console.log(array)
    for(let i = 0; i < A.length; ++i) {
        if(!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Analysis

expand all Example tests

▶

example1
the first example test

✔

0.076 s

stdout:

[ true, true, true, true ]

▶

example2
the second example test

✔

0.072 s

stdout:

should not hit

Code: 16:05:31 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            return 0;
        }
        array[A[i] - 1] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:05:51 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Early rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            return 0;
        }
        array[A[i] - 1] = true;
    }

    for(let i = 0; i < A.length; ++i) {
        if(!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:06:01 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Early rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            return 0;
        }
        array[A[i] - 1] = true;
    }

    // Check again if 
    for(let i = 0; i < A.length; ++i) {
        if(!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Code: 16:06:16 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Early rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            return 0;
        }
        array[A[i] - 1] = true;
    }

    // Check again if we have any holes in our array, once found, reject again.
    for(let i = 0; i < A.length; ++i) {
        if(!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Analysis

expand all Example tests

▶

example1
the first example test

✔

0.072 s

▶

example2
the second example test

✔

0.072 s

Code: 16:06:19 UTC, js, final, score: 100

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)

    // Think of these are fake 
    let array = [];
    
    for(let i = 0; i < A.length; ++i) {
        // Early rejection check for duplication or if it's bigger than our length
        if (array[A[i] - 1] || A[i] > A.length) {
            return 0;
        }
        array[A[i] - 1] = true;
    }

    // Check again if we have any holes in our array, once found, reject again.
    for(let i = 0; i < A.length; ++i) {
        if(!array[i]) {
            return 0;
        }
    }
    
    
    return 1;
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

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

expand all Example tests

▶

example1
the first example test

✔

0.072 s

▶

example2
the second example test

✔

0.072 s

expand all Correctness tests

▶

extreme_min_max
single element with minimal/maximal value

✔

0.072 s

▶

single
single element

✔

0.072 s

▶

double
two elements

✔

0.072 s

▶

antiSum1
total sum is correct, but it is not a permutation, N <= 10

✔

0.072 s

▶

small_permutation
permutation + one element occurs twice, N = ~100

✔

0.072 s

▶

permutations_of_ranges
permutations of sets like [2..100] for which the anwsers should be false

✔

0.072 s

expand all Performance tests

▶

medium_permutation
permutation + few elements occur twice, N = ~10,000

✔

0.084 s

▶

antiSum2
total sum is correct, but it is not a permutation, N = ~100,000

✔

0.108 s

0.116 s

▶

large_not_permutation
permutation + one element occurs three times, N = ~100,000

✔

0.124 s

▶

large_range
sequence 1, 2, ..., N, N = ~100,000

✔

0.116 s

0.112 s

▶

extreme_values
all the same values, N = ~100,000

✔

0.072 s

0.096 s

0.072 s

▶

various_permutations
all sequences are permutations

✔

0.072 s

0.084 s

0.116 s

0.124 s