[codility] AbsDistinct

A non-empty array A consisting of N numbers is given. The array is sorted in non-decreasing order. The absolute distinct count of this array is the number of distinct absolute values among the elements of the array.

For example, consider array A such that:

  A[0] = -5
  A[1] = -3
  A[2] = -1
  A[3] =  0
  A[4] =  3
  A[5] =  6
The absolute distinct count of this array is 5, because there are 5 distinct absolute values among the elements of this array, namely 0, 1, 3, 5 and 6.

Write a function:

class Solution { public int solution(int[] A); }

that, given a non-empty array A consisting of N numbers, returns absolute distinct count of array A.

For example, given array A such that:

  A[0] = -5
  A[1] = -3
  A[2] = -1
  A[3] =  0
  A[4] =  3
  A[5] =  6
the function should return 5, as explained above.

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 [−2,147,483,648..2,147,483,647];
array A is sorted in non-decreasing order.
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문제안에 답이있는..

 

절대값 중복제거 

Math.abs 가 절대값이고 Set 으로 중복제거를  했더니 통과..

easy 는 easy 인데..

 

public static int solution(int[] A) {
    int ret = 0;
    Set<Integer> set = new HashSet<>();
    for (int aa : A){
        set.add(Math.abs(aa));
    }
    ret = set.size();
    return ret;
}