B. Approximating a Constant Range

#include <iostream>
using namespace std;

int main()
{
    int n;
    cin >> n;
    int a[1000005] = {0};
    int ans = 0;
    for(int i = 0; i < n; ++i)
    {
        int tmp;
        cin >> tmp;
        a[tmp + 1]++;
        a[tmp]++;
        a[tmp + 2] = a[tmp - 1] = 0;
        ans = max(ans, max(a[tmp], a[tmp + 1]));
    }
    cout << ans << endl;
    return 0;
}