input:light.in output:light.out

时间限制: 1000 ms 空间限制: 524288 KB

题目描述

输入

输出

样例输入

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2
5
1 1 0 1 1

样例输出

1
3

数据范围限制

提示

按动 1、4 、5 号开关

代码

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#include <bits/stdc++.h>
#define rr register
int n,a[100005],ans;
signed main()
{
    freopen("light.in","r",stdin);
    freopen("light.out","w",stdout);
    scanf("%d",&n);
    for(rr int i=1;i<=n;i++)
        scanf("%d",&a[i]);
    for(rr int i=n;i>=1;i--)
    {
        if(a[i])
        {
            ans++;
            a[i]=false;
            for(rr int j=1;j<=sqrt(i);j++)
            {
                if(i%j==0 && j==sqrt(i))
                {
                    a[j]=!a[j];
                    continue;
                }
                if(i%j==0)
                {
                    a[j]=!a[j];
                    a[i/j]=!a[i/j];
                }
            }
        }
    }
    printf("%d",ans);
}