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: Accepted)

#include <stdlib.h>
#include <stdio.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>

int search(int x, int array[], int N)
{
    for (int i = 0; i < N; i++)
    {
        if (x == array[i])
            return 1;
    }

    return 0;
}

int main()
{
    int X, N;

    scanf("%d %d", &X, &N);

    int arr[101];
    int p[N];

    if (X == 0)
    {
      printf("-1");
      return 0;

    } 

    if (N == 0)
    {
        printf("%d", X);
        return 0;
    }

    for (int i = 0; i < 101; i++)
    {
        arr[i] = 200;
    }

    for (int i = 0; i < N; i++)
    {
        scanf("%d", &p[i]);
    }

    for (int i = 0; i <= 101; i++)
    {
        if (search(i, p, N) == 0)
            arr[i] = i ;
    }

    //     for (int i = 0; i < 100; i++)
    //         {
    //             printf("%d  ",arr[i]);
    //         }
    //   printf("\n");
    for (int i = 0; i <= 101; i++)
    {
        if (arr[i] != 200)
        {
            arr[i] = abs(X - arr[i]);
        }
    }
    
    int min = INT_MAX;
    int idx = 0;

    //    for (int i = 0; i <= 101; i++)
    //     {
    //         printf("%d | ",arr[i]);
    //     }
    // printf("\n");

    for (int i = 0; i <= 101; i++)
    {
        if (arr[i] != 200)
        {
            if (min > arr[i])
            {
                min = arr[i];
                idx = i;
            }
        }
    }

    printf("%d", idx );
}