Submission #1007709

#	Time	Username	Problem	Language	Result	Execution time	Memory
1007709		VMaksimoski008	Hacker (BOI15_hac)	C++17	100 / 100	397 ms	45992 KiB

hac

#include <bits/stdc++.h>

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
//#define int long long

using namespace std;

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;

struct SegTree {
    int n;
    vector<ll> tree, lazy;

    SegTree(int _n) : n(_n), tree(4*_n+5, 1e18), lazy(4*_n+5, 1e18) {}

    void push(int u, int tl, int tr) {
        if(lazy[u] == 1e18) return ;
        tree[u] = min(tree[u], lazy[u]);

        if(tl != tr) {
            lazy[2*u] = min(lazy[u], lazy[2*u+1]);
            lazy[2*u+1] = min(lazy[u], lazy[2*u+1]);
        }

        lazy[u] = 1e18;
    }

    void update(int u, int tl, int tr, int l, int r, ll v) {
        push(u, tl, tr);
        if(tl > tr || l > tr || tl > r) return ;

        if(l <= tl && tr <= r) {
            lazy[u] = min(lazy[u], v);
            push(u, tl, tr);
            return ;
        }

        int tm = (tl + tr) / 2;
        update(2*u, tl, tm, l, r, v);
        update(2*u+1, tm+1, tr, l, r, v);
        tree[u] = min(tree[2*u], tree[2*u+1]);
    }

    ll query(int u, int tl, int tr, int l, int r) {
        if(tl > tr || l > tr || tl > r) return 1e18;
        push(u, tl, tr);
        if(l <= tl && tr <= r) return tree[u];
        int tm = (tl + tr) / 2;
        return min(query(2*u, tl, tm, l, r), query(2*u+1, tm+1, tr, l, r));
    }

    void update(int l, int r, ll v) { update(1, 0, n-1, l, r, v); }
    ll query(int l, int r) { return query(1, 0, n-1, l, r); }
};

signed main() {
    int n;
    cin >> n;

    vector<int> v(n+1);
    for(int i=1; i<=n; i++) cin >> v[i];
    for(int i=1; i<=n; i++) v.push_back(v[i]);

    vector<ll> pref(2*n+1);
    for(int i=1; i<=2*n; i++) pref[i] = pref[i-1] + v[i];

    SegTree tree(n+1);
    int len = (n + 1) / 2;
    for(int i=1; i<=n; i++) {
        ll val = pref[i+len-1] - pref[i-1];
        if(i+len-1 <= n) tree.update(i, i+len-1, val);
        else {
            tree.update(i, n, val);
            tree.update(1, i+len-1-n, val);
        }
    }

    ll ans = 0;
    for(int i=1; i<=n; i++) ans = max(ans, tree.query(i, i));
    cout << ans << '\n';
    return 0;
}

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