[Codeforces]1100A. Roman and Browser

題目來源: https://codeforces.com/problemset/problem/1100/A
這題單純地將間格以依序取出("+1總數"-間隔+1數量)-("-1總數"-間隔-1數量)的最大值

#pragma gcc optimize("o2")
#include<bits/stdc++.h>
#define IO ios_base::sync_with_stio(false)
#define CI cin.tie(NULL)
#define int long long int
using namespace std;
signed main()
{
    int n,k,po=0,ne=0,str[1005];
    cin >> n >>k;
    int times=k;
    for(int i=1;i<=n;i++)
    {
        cin >> str[i];

        if(str[i]==1)

            po++;

        else

            ne++;

    }
    //cout << po << " " << ne <<endl;
    int flag=0,totalne[1005]={0},totalpo[1005]={0};
    while(times--)
    {
        flag++;

        for(int i=flag;i<=n;i+=k)

        {

            //cout << "i=" <<i <<endl;

            if(str[i]==-1)

                totalne[flag]++;

            else if(str[i]==1)

                totalpo[flag]++;

        }

    }
    //for(int i=1;i<=flag;i++)
    //cout << totalne[i] <<" " << totalpo[i] <<endl;
    int maxu=0;
    for(int i=1;i<=flag;i++)
        maxu=max(maxu,abs((po-totalpo[i])-(ne-totalne[i])));

    cout << maxu<<endl;
    return 0;
}