Codeforces 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 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 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 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.

 

Input

5
1 0 0 1 0

Output

4

Input

4
1 0 0 1

Output

4

题目大意：这题目就只要选 一个范围，然后使这个范围中 0变成1  1变成0  然后统计变换之后 1最多会有多少个  比较简单

代码实现：

#include <stdio.h>
int main()
{
    int n ;
    while( ~scanf("%d" , &n ) )
    {
        int max = -1,res = 0;
        int cou = 0;
        for ( int i = 0 ; i < n ; i++ )
        {
            int a;
            scanf("%d",&a);
            if ( a == 0 )
            {
                cou++ ;
            }
            else 
            {
                res++;
                cou -- ;
            }
            if (cou > max ) max = cou;
            if ( cou < 0) cou = 0; 
        }
        printf("%d\n",max+res);
    }
    return 0;
}