CF 327A - Flipping Game

A. Flipping Game

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Iahub got bored, so he invented a game to be played on paper.

He writes n integers a₁, a₂, ..., a_n. Each of those integers can be either 0 or 1. He's allowed to do exactly one move: he chooses two indicesi and j (1 ≤ i ≤ j ≤ n) and flips all valuesa_k for which their positions are in range[i, j] (that is i ≤ k ≤ j). Flip the value of x means to apply operation x = 1 -x.

The goal of the game is that after exactly one move to obtain the maximum number of ones. Write a program to solve the little game of Iahub.

Input

The first line of the input contains an integer n (1 ≤ n ≤ 100). In the second line of the input there aren integers: a₁, a₂, ..., a_n. It is guaranteed that each of those n values is either 0 or 1.

Output

Print an integer — the maximal number of 1s that can be obtained after exactly one move.

Sample test(s)

Input

51 0 0 1 0

Output

4

Input

41 0 0 1

Output

4

Note

In the first case, flip the segment from 2 to 5 (i = 2, j = 5). That flip changes the sequence, it becomes: [1 1 1 0 1]. So, it contains four ones. There is no way to make the whole sequence equal to [1 1 1 1 1].

In the second case, flipping only the second and the third element (i = 2, j = 3) will turn all numbers into 1.

http://codeforces.com/problemset/problem/327/A

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;#define N 110int main(){int i,j,k,n,res,mx;while(~scanf("%d",&n)){for(i=1,k=mx=res=0;i<=n;i++){scanf("%d",&j);res+=j;if(j==1){if(k>0)k--;}else k++;mx=max(mx,k);}res+=mx;if(mx<=0)res--;printf("%d\n",res);}return 0;}