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.Scanner;

public class Main {
	public static void main(String[] args) {
		// 入力の受け取り
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int N = sc.nextInt();
		int[] P = new int[N];
		for (int i = 0; i < N; i++) {
			P[i] = sc.nextInt();
		}
		int[] array = new int[103];
		for (int i = 0; i < 103; i++) {
			array[i] = i - 1;
		}
		for (int i = 0; i < N; i++) {
			array[P[i] + 1] = -100;
		}
		
//		for (int i = 0; i < array.length; i++) {
//			System.out.println(array[i]);
//		}
		

		int dis = X - array[0];
		int ans = array[0];
		for (int i = 1; i < array.length; i++) {
			if (Math.abs(X - array[i]) < dis) {
				dis = X - array[i];
				ans = array[i];
			}
		}
		System.out.println(ans);

		sc.close();
	}
}