Submission #752545

#	Time	Username	Problem	Language	Result	Execution time	Memory
752545		GrindMachine	Hacker (BOI15_hac)	C++17	40 / 100	1096 ms	1236 KiB

hac

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
https://github.com/Raghavan098/CP-Codes/blob/master/Baltic/Baltic%2015-hac.cpp

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

void solve(int test_case)
{
    ll n; cin >> n;
    vector<ll> a(n);
    rep(i,n) cin >> a[i];

    ll suma = 0;
    rep(i,n) suma += a[i];

    ll ans = 0;

    rep(hack,n){
        ll sum = 0;
        rep(i,n/2) sum += a[i];

        ll mx = 0;

        rep(l,n){
            ll r = (l+n/2-1)%n;
            if(l){
                sum += a[r];
                sum -= a[l-1];
            }

            bool good = false;

            if(l <= r){
                if(l <= hack and hack <= r){

                }
                else{
                    good = true;
                }
            }
            else{
                if(hack >= l or hack <= r){

                }
                else{
                    good = true;
                }
            }

            if(good){
                amax(mx, sum);
            }
        }

        amax(ans, suma - mx);
    }

    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 40