Codility PermMissingElem Solution

Codility PermMissingElem Solution

import java.util.Arrays;
import java.util.stream.IntStream;
import java.util.stream.Collectors;

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        int first=0;
        int last=A.length;
        if(last==first){
         return 1;   
        }
        int [] sorted=IntStream.of(A).sorted().toArray();
        
       for(int index=0;index<A.length;index++){
           int check=index+1;   
          
           if(!sort(sorted,first,last,check)){
               return check;
           }
           
           
       }    
       return A.length+1;
    }
    
    private boolean sort(int[] L,int low,int high,int k){
        int mid = (low + high) / 2;
    if (mid>L.length||low > high) {
        return false;
    } else if (L[mid] == k) {
        return true;
    } else if (L[mid] < k) {
        return sort(L, mid + 1, high, k);
    } else {
        return sort(L, low, mid - 1, k);
    }
        
    }
}