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 C++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int absolute(int a){
    return a > 0 ? a : a*-1;
}
bool contains(int size,int* a,int target){
    for(int i = 0;i<size;i++){
        if(a[i] == target){
            return true;
        }
    }
    return false;
}

int main() {
    int a,b,temp,temp1;
    temp = 0;
    temp1 = 0;
    cin >> a >>b;
    if(b == 0){
        cin >> temp;
        cout << a << endl;
        return 0;
    }
    int c[b];
    int d[100];
    for(int i = 0;i<100;i++){
        d[i] = i+1;
    }
    for(int i = 0;i<b;i++){
        cin >> c[i];
    }
    for(int i = 0;i<100;i++){
        if(!contains(b,c,i+1)){
            if(i == 0){
                temp = 1;
                temp1 = absolute(a-(i+1));
            }else{
                if(temp1 > absolute(a-(i+1))){
                    temp = i+1;
                    temp1 = absolute(a-(i+1));
                }
            }
        }
    }
    cout << temp << endl;


}