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: 21:24:09 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) {
        // write your code in Java SE 8
    }
}

Code: 21:24:14 UTC, js, autosave

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// 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)
}

Code: 21:24:24 UTC, js, autosave

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

function solution(A) {
    
}

Code: 21:24:46 UTC, js, autosave

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1 2 3

function solution(A) {
    A = A.sort(function)    
}

Code: 21:25:16 UTC, js, autosave

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1 2 3 4 5

function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    }))    
}

Code: 21:25:46 UTC, js, autosave

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1 2 3 4 5 6

function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    }));
    for (var j = 0; j < A.length; )
}

Code: 21:25:57 UTC, js, autosave

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function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    }));
    for (var j = 0; j < A.length; ){
    }
    }
}

Code: 21:26:18 UTC, js, autosave

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1 2 3 4 5 6 7 8

function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    }));
    for (var j = 0; j < A.length; ){
        if (A[j] == ++j){
    }
}

Code: 21:26:48 UTC, js, autosave

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1 2 3 4 5 6 7 8 9 10 11

function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    }));
    for (var j = 0; j < A.length; ) {
        if (A[j] == ++j) {
            continue
        }
        else {}
    }
}

Code: 21:27:06 UTC, js, verify, result: Failed

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function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    }));
    for (var j = 0; j < A.length; ) {
        if (A[j] == ++j) {
            continue
        }
        else {return 0}
    }
    return 1
}

Analysis

expand all Example tests

▶

example1
the first example test

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.072 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

solution.js:4
    }));
      ^

SyntaxError: Unexpected token )
    at createScript (vm.js:80:10)
    at Object.runInNewContext (vm.js:135:10)
    at getSolution (/tmp/exec.js:392:29)
    at Promise.resolve.then (/tmp/exec.js:426:34)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
    at Function.Module.runMain (module.js:686:11)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3

▶

example2
the second example test

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.072 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

solution.js:4
    }));
      ^

SyntaxError: Unexpected token )
    at createScript (vm.js:80:10)
    at Object.runInNewContext (vm.js:135:10)
    at getSolution (/tmp/exec.js:392:29)
    at Promise.resolve.then (/tmp/exec.js:426:34)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
    at Function.Module.runMain (module.js:686:11)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3

Code: 21:27:28 UTC, js, autosave

show code in pop-up

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function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    });
    for (var j = 0; j < A.length; ) {
        if (A[j] == ++j) {
            continue
        }
        else {return 0}
    }
    return 1
}

Code: 21:27:33 UTC, js, verify, result: Passed

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function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    });
    for (var j = 0; j < A.length; ) {
        if (A[j] == ++j) {
            continue
        }
        else {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: 21:27:43 UTC, js, verify, result: Passed

show code in pop-up

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

function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    });
    for (var j = 0; j < A.length; ) {
        if (A[j] == ++j) {
            continue
        }
        else {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: 21:27:45 UTC, js, final, score: 100

show code in pop-up

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

function solution(A) {
    A = A.sort(function(a, b) {
        return a - b
    });
    for (var j = 0; j < A.length; ) {
        if (A[j] == ++j) {
            continue
        }
        else {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

0.068 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

✔

0.088 s

0.072 s

▶

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

✔

0.072 s

0.084 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

✔

0.112 s

▶

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

✔

0.204 s

0.196 s

▶

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

✔

0.212 s

▶

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

✔

0.208 s

0.204 s

▶

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

✔

0.072 s

0.108 s

0.072 s

▶

various_permutations
all sequences are permutations

✔

0.068 s

0.072 s

0.108 s

0.196 s

0.212 s