cf div2 191 A

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 indices i and j (1 ≤ i ≤ j ≤ n) and flips all values a_k for which their positions are in range [i, j] (that is i ≤ k ≤ j). Flip the value of xmeans 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 are n 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

一道水题，下面是代码：

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;int main(){    int n;    int a[10000];    while(scanf("%d",&n)!=EOF){        for(int i=0;i<n;i++){              scanf("%d",&a[i]);        }        int ans=0;        for(int i=0;i<n;i++)           for(int j=i;j<n;j++){                int sum=0;               for(int k=0;k<n;k++){                       if(k<i||k>j){                           if(a[k]==1){                             sum++;                           }                       }                        else if(a[k]==0){                             sum++;                        }               }               ans=sum>ans?sum:ans;           }               cout<<ans<<endl;    }    return 0;}