Problem:
Score : 300 points

Problem Statement

You are given an integer sequence of length N, a_1,a_2,...,a_N.

For each 1≤i≤N, you have three choices: add 1 to a_i, subtract 1 from a_i or do nothing.

After these operations, you select an integer X and count the number of i such that a_i=X.

Maximize this count by making optimal choices.

Constraints

1≤N≤10^5

0≤a_i<10^5 (1≤i≤N)

a_i is an integer.

Input

The input is given from Standard Input in the following format:

N
a_1 a_2 .. a_N

Output

Print the maximum possible number of i such that a_i=X.

Sample Input 1

7
3 1 4 1 5 9 2

Sample Output 1

4

For example, turn the sequence into 2,2,3,2,6,9,2 and select X=2 to obtain 4, the maximum possible count.

Sample Input 2

10
0 1 2 3 4 5 6 7 8 9

Sample Output 2

3

Sample Input 3

1
99999

Sample Output 3

1

Solution in C++14 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

void a()
{
   int X, t;
    cin >> X >> t;
    if(X <= t)
    {
        cout << 0 << endl;
    }else{

        cout << X - t << endl;
    }
}

void b()
{
    string s;
    cin >> s;
    for(int i = 0; i < s.size(); i++)
    {
        if ((i % 2) == 0)
        {
            cout << s[i];
        }
    }
    cout << endl;
}

void c()
{
    int n;
    cin >> n;
    vector<int> a(n);
    int maxv = 0, minv = 100000;
    for(int i = 0; i < n; i++)
    {
        cin >> a[i];
        if(a[i] > maxv)
        {
            maxv = a[i];
        }
        if(a[i] < minv)
        {
            minv = a[i];
        }
    }
    sort(a.begin(), a.end());
    maxv = a[n / 2];minv--;
    maxv++;
    int maxcount = 0;
    for(int i= minv; i <= maxv; i++)
    {
        int count = 0;
        for(auto e : a) {
            if (e == i) count++;
            if ((e - 1) == i)count++;
            if ((e + 1) == i) count++;
        }
        if(count > maxcount) maxcount = count;
    }
    cout << maxcount << endl;
}

int main() {
    c();
    return 0;
}