A_Flipping_Game.cpp

// Link: https://codeforces.com/problemset/problem/327/A

/*

||-------------------------------||
||      Mohiul Islam Miraz       ||
||-------------------------------||

*/

#include <bits/stdc++.h>
#define swift                     \
    ios_base::sync_with_stdio(0); \
    cin.tie(NULL);
#define sac sort(v.begin(), v.end())
#define sdc sort(v.begin(), v.end(), greater<int>())
#define f1 bool flag = true
#define f0 bool flag = false
#define c0 int count = 0
#define c1 int count = 1
#define s0 long long sum = 0
#define a0 long long ans = 0
#define ll long long
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define minus cout << -1 << endl
#define cnt cout << count << endl
#define sm cout << sum << endl
using namespace std;

int main()
{
    swift;
    int t = 1;
    // cin >> t;

    while (t--)
    {
        int n; cin >> n;
        vector<int>v(n);
        for (int i = 0; i < n; i++) cin >> v[i];

        int count1 = 0, extra0 = 0, extra0max = -1;
        for (int i = 0; i < n; i++)
        {
            if (v[i] == 1)
            {
                count1 += 1;
                if (extra0 > 0)
                {
                    extra0 -= 1;
                }
            }
            else
            {
                extra0 += 1;
                if (extra0 > extra0max)
                {
                    extra0max = extra0;
                }
            }
        }
        cout << count1 + extra0max << endl;
    }

    return 0;
}