PermCheck Codility












0












$begingroup$


The following code gets 100% on the PermCheck task on Codility, it should be O(N).



The question is:




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
A1 = 1
A[2] = 3
A[3] = 2



is a permutation, but array A such that:
A[0] = 4
A1 = 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
A1 = 1
A[2] = 3
A[3] = 2



the function should return 1.



Given array A such that:
A[0] = 4
A1 = 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].



Let me know if you think it can be improved, but I think it is pretty good. ;)



function solution(A) {
let m = A.length;
let sumA = A.reduce((partial_sum, a) => partial_sum + a);
let B = Array.apply(null, Array(m)).map(function () {});
var sum_indices = 0;
for (var i = 0; i < m; i++) {
B[A[i] - 1] = true;
sum_indices += i + 1;
}
if (sum_indices == sumA && B.indexOf(undefined) == -1) {
return 1;
} else {
return 0;
}
}








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    0












    $begingroup$


    The following code gets 100% on the PermCheck task on Codility, it should be O(N).



    The question is:




    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
    A1 = 1
    A[2] = 3
    A[3] = 2



    is a permutation, but array A such that:
    A[0] = 4
    A1 = 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
    A1 = 1
    A[2] = 3
    A[3] = 2



    the function should return 1.



    Given array A such that:
    A[0] = 4
    A1 = 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].



    Let me know if you think it can be improved, but I think it is pretty good. ;)



    function solution(A) {
    let m = A.length;
    let sumA = A.reduce((partial_sum, a) => partial_sum + a);
    let B = Array.apply(null, Array(m)).map(function () {});
    var sum_indices = 0;
    for (var i = 0; i < m; i++) {
    B[A[i] - 1] = true;
    sum_indices += i + 1;
    }
    if (sum_indices == sumA && B.indexOf(undefined) == -1) {
    return 1;
    } else {
    return 0;
    }
    }








    share







    New contributor




    James Ray is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.







    $endgroup$















      0












      0








      0





      $begingroup$


      The following code gets 100% on the PermCheck task on Codility, it should be O(N).



      The question is:




      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
      A1 = 1
      A[2] = 3
      A[3] = 2



      is a permutation, but array A such that:
      A[0] = 4
      A1 = 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
      A1 = 1
      A[2] = 3
      A[3] = 2



      the function should return 1.



      Given array A such that:
      A[0] = 4
      A1 = 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].



      Let me know if you think it can be improved, but I think it is pretty good. ;)



      function solution(A) {
      let m = A.length;
      let sumA = A.reduce((partial_sum, a) => partial_sum + a);
      let B = Array.apply(null, Array(m)).map(function () {});
      var sum_indices = 0;
      for (var i = 0; i < m; i++) {
      B[A[i] - 1] = true;
      sum_indices += i + 1;
      }
      if (sum_indices == sumA && B.indexOf(undefined) == -1) {
      return 1;
      } else {
      return 0;
      }
      }








      share







      New contributor




      James Ray is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.







      $endgroup$




      The following code gets 100% on the PermCheck task on Codility, it should be O(N).



      The question is:




      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
      A1 = 1
      A[2] = 3
      A[3] = 2



      is a permutation, but array A such that:
      A[0] = 4
      A1 = 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
      A1 = 1
      A[2] = 3
      A[3] = 2



      the function should return 1.



      Given array A such that:
      A[0] = 4
      A1 = 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].



      Let me know if you think it can be improved, but I think it is pretty good. ;)



      function solution(A) {
      let m = A.length;
      let sumA = A.reduce((partial_sum, a) => partial_sum + a);
      let B = Array.apply(null, Array(m)).map(function () {});
      var sum_indices = 0;
      for (var i = 0; i < m; i++) {
      B[A[i] - 1] = true;
      sum_indices += i + 1;
      }
      if (sum_indices == sumA && B.indexOf(undefined) == -1) {
      return 1;
      } else {
      return 0;
      }
      }






      javascript combinatorics





      share







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      James Ray is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.










      share







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      James Ray is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.








      share



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      asked 7 mins ago









      James RayJames Ray

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      New contributor





      James Ray is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.






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      Check out our Code of Conduct.






















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