Submission #1088397

#	Time	Username	Problem	Language	Result	Execution time	Memory
1088397		steveonalex	Hacker (BOI15_hac)	C++17	100 / 100	138 ms	30272 KiB

hac

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
#define block_of_code if(true)
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }
 
const ll INF = 1e18;
struct SegmentTree{
    int n;
    vector<ll> a;

    SegmentTree(int _n){
        n = _n;
        a.resize(n * 2 + 2, INF);
    }

    void update(int i, ll v){
        i += n; a[i] = v;
        while(i > 1){
            i >>= 1;
            a[i] = min(a[i * 2], a[i * 2 + 1]);
        }
    }

    ll get(int l, int r){
        l += n; r += n + 1;
        ll ans = INF;
        while(l < r){
            if (l & 1) minimize(ans, a[l++]);
            if (r & 1) minimize(ans, a[--r]);
            l >>= 1; r >>= 1;
        }
        return ans;
    }
};
 
int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    clock_t start = clock();

    int n; cin >> n;
    vector<int> a(n * 2);
    for(int i = 0; i<n; ++i) cin >> a[i];

    int k = (n + 1) / 2;
    for(int i = n; i<n*2; ++i) a[i] = a[i-n];

    vector<ll> what;
    ll sum = 0;
    for(int i = 0; i<k-1; ++i){
        sum += a[i];
    }
    for(int i = k-1; i<n+k-1; ++i){
        sum += a[i];
        what.push_back(sum);
        sum -= a[i - k + 1];
    }

    for(int i = 0; i<n; ++i) what.push_back(what[i]);

    SegmentTree st(n * 2);
    for(int i = 0; i<n*2; ++i) st.update(i + 1, what[i]);

    ll ans = 0;
    for(int i = k; i<=n*2; ++i){
        maximize(ans, st.get(i - k + 1, i));
    }
    cout << ans << "\n";
 
    cerr << "Time elapsed: " << clock() - start << " ms\n";
    return 0;
}

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