코딩테스트#013 Distinct

A Kind Dev·2023년 2월 1일
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코딩테스트

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13/19

문제

Write a function

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

that, given an array A consisting of N integers, returns the number of distinct values in array A.

For example, given array A consisting of six elements such that:

A[0] = 2 A[1] = 1 A[2] = 1
A[3] = 2 A[4] = 3 A[5] = 1
the function should return 3, because there are 3 distinct values appearing in array A, namely 1, 2 and 3.

Write an efficient algorithm for the following assumptions:

  • N is an integer within the range [0..100,000];
  • each element of array A is an integer within the range [−1,000,000..1,000,000].

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나의 풀이

import java.util.*;

class Solution {
    public int solution(int[] A) {
        
        Set<Integer> set = new HashSet<>();

        for (int a : A) {
            set.add(a);
        }

        return set.size();
    }
}

check 1 : set의 성질 (중복 제거)

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