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 Python (3.8.2) (judge verdict: Wrong Answer)

import bisect
import numpy as np

X, N = map(int, input().split())
p_array = np.array(list(map(int, input().split())))

if N ==0:
    print(X)

else:
    p_array = sorted(p_array)

    left = bisect.bisect_left(p_array, X) - 1
    right = left + 2

    i = left
    left_answer = X - 1
    while True:
        if i <= 0:
            left_answer -= 1
            break

        if p_array[i] == left_answer:
            i -= 1
            left_answer -= 1
        else:
            break

    j = right
    right_answer = X + 1
    while True:
        if j >= N:
            right_answer += 1
            break

        if p_array[j] == right_answer:
            j += 1
            right_answer += 1
        else:
            break

    if X - left_answer <= right_answer - X:
        print(left_answer)
    else:
        print(right_answer)