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 1.8.0) (judge verdict: Wrong Answer)

import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc=new Scanner(System.in);

		int x=sc.nextInt();
		int n=sc.nextInt();		//数字列の長さ

		ArrayList<Integer>array=new ArrayList<>();
		for(int i=0;i<n;i++) {
			array.add(sc.nextInt());
		}
		
		if(n==0) {
			System.out.println(x);
		}else {
			int mincount = 0;
			int min = 0;
			for(int i=0;i<100;i++) {

				//String b = Integer.toString(i);

				if(!array.contains(i)) {
					int aaa = x-i;
					aaa = Math.abs(aaa);
					if(mincount==0) {
						min = i;
						mincount = aaa;
					}else if(mincount>aaa) {
						mincount = aaa;
						min = i;
					}else if(mincount==aaa) {
						if(min>i) {
							mincount =aaa;
							min = i;

						}
					}

				}

			}
			System.out.println(min);
		}
	
	}

}