eeee

试改本帖作者的运气代码以此AC所有测试点（

#include<iostream>
#include<vector>
#include<algorithm>
#include<climits>
#include<omp.h>
#define IOS ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define QWQ return 0;
#define ll long long
using namespace std;
ll f(const vector<ll>&p,const ll c,const vector<bool>&r){
    ll n=p.size();
    vector<ll>g=p;
    for(ll i(0);i<n;++i){
        if(r[i]){
            ll l=(i-1+n)%n;ll m=(i+1)%n;
            g[l]-=c;g[m]-=c;
        }
    }
    ll t=0;
    for(ll i(0);i<n;++i){
        if(r[i]){t+=g[i];}
    }
    return t;
}
ll m(const vector<ll>&p,const ll c){
    ll n=p.size();ll ma=LLONG_MIN;
    #pragma omp parallel for reduction(max:ma)
    for(ll i(0);i<(1<<n);++i){
        vector<bool>r(n,false);
        for(ll j(0);j<n;++j){
            if(i&(1<<j)){r[j]=true;}
        }
        ll cur=f(p,c,r);
        #pragma omp critical
        {
            ma=max(ma,cur);
        }
    }
    return ma;
}
signed main(void){
    IOS
    ll n,c;
    cin>>n>>c;
    vector<ll>p(n);
    for(ll i(0);i<n;++i){cin>>p[i];}
    if(n==1){cout<<0;}else{cout<<m(p,c);}
    QWQ
}