[Codility Lessons] MissingInteger(9/n)

[Lesson4] Counting Elements

MissingInteger : Find the smallest positive integer that does not occur in a given sequence.

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Java Solution

import java.util.*;

class Solution {
    public int solution(int[] A) {
        HashSet<Integer> arr = new HashSet<Integer>();
        // A 배열을 arr HashSet에 입력
        for(int i = 0; i < A.length; i++){
            if(A[i] > 0){
                arr.add(A[i]);    
            }  
        }
        // A 배열에 있는 순열 값 + 1 리턴
        for(int i = 1; i <= arr.size(); i++){
            if(!arr.contains(i)){
                return i;
            }
        }
        // A 배열 순열일 경우 크기 + 1 리턴
        return arr.size()+1;
    }
}

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PHP Solution

function solution($A) {
    $arr = array();
    foreach($A as $value){
        if($value > 0 && !isset($arr[$value])){
            $arr[$value] = $value;
        }    
    }
    for($i = 1; $i <= count($arr); $i++){
        if(!isset($arr[$i])){
            return $i;    
        }
    }
    return count($arr)+1;
}