Problem:
Score : 300 points

Problem Statement

Given are an integer X and an integer sequence of length N: p_1, \ldots, p_N.

Among the integers not contained in the sequence p_1, \ldots, p_N (not necessarily positive), find the integer nearest to X, that is, find the integer whose absolute difference with X is the minimum. If there are multiple such integers, report the smallest such integer.

Constraints

1 \leq X \leq 100

0 \leq N \leq 100

1 \leq p_i \leq 100

p_1, \ldots, p_N are all distinct.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

X N
p_1 ... p_N

Output

Print the answer.

Sample Input 1

6 5
4 7 10 6 5

Sample Output 1

8

Among the integers not contained in the sequence 4, 7, 10, 6, 5, the one nearest to 6 is 8.

Sample Input 2

10 5
4 7 10 6 5

Sample Output 2

9

Among the integers not contained in the sequence 4, 7, 10, 6, 5, the ones nearest to 10 are 9 and 11. We should print the smaller one, 9.

Sample Input 3

100 0

Sample Output 3

100

When N = 0, the second line in the input will be empty. Also, as seen here, X itself can be the answer.

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int x = sc.nextInt();
        int n = sc.nextInt();
        if(n==0){
            System.out.println(x);
            System.exit(0);
        }
        int number[] = new int[201];
        Arrays.fill(number,1);
        for(int i=0;i<n;i++){
            int p = sc.nextInt();
            number[p]=0;
        }
        for(int i=0;i<=200;i++){
            if(x-i <= 0)continue;
            if(x+i > 200)continue;
            if(number[x-i]==1){
                System.out.println(x-i);
                System.exit(0);
            }
            if(number[x+i]==1){
                System.out.println(x+i);
                System.exit(0);
            }
        }
        System.out.println(0);//配列全て0で埋まっている
    }
}

class Monmo {
    
}