Submission #959601

#	Time	Username	Problem	Language	Result	Execution time	Memory
959601		ALTAKEXE	Tortoise (CEOI21_tortoise)	C++17	100 / 100	56 ms	10256 KiB

tortoise

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
const int N = 505050;
 
int n, a[N], l[N], r[N], s[N];
 
int main() {
    cin.tie(0); ios_base::sync_with_stdio(0);
    cin >> n;
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        if (a[i] != -1)
            ans += a[i];
    }
 
    int p = -1, q = -1, y = -1;
    for (int i = 1; i <= n; i++) {
        if (a[i] == -1)
            p = i;
        else {
            if (p != -1)
                l[i] = p;
        }
    }
    p = -1;
    for (int i = n; i >= 1; i--) {
        if (a[i] == -1)
            p = i;
        else if (a[i]) {
            if (p != -1)
                r[i] = p;
 
            if (q != -1)
                s[i] = q;
            else
                y = i;
            
            q = i;
        }
    }
 
    map<int, int> mp;
    priority_queue<int> pq;
    ll sum = 0;
    for (int i = 1; i <= n; i++) {
        if (a[i] <= 0) 
            continue;
        
        int d = 1e9;
        if (l[i])
            d = min(d, 2 * (i - l[i]));
        if (r[i])
            d = min(d, 2 * (r[i] - i));
        
        int f = d;
        if (s[i] && r[i]) {
            if (s[i] < r[i])
                f = min(f, 2 * (r[i] - s[i]));
            else
                f = 0;
        }
 
        if (i == y)
            f = 0;
 
        --a[i];
        while (a[i] && sum + (i - 1) <= 2 * (i - 1)) {
            mp[d]++;
            sum += d;
            --a[i];
        }
 
        if (a[i]) {
            if (prev(mp.end())->first >= d) {
                mp[d] += a[i];
                sum += 1ll * d * a[i];
            }   
 
            while (!mp.empty() && sum + (i - 1) > 2 * (i - 1)) {
                auto [a, b] = *prev(mp.end());
 
                if (sum - 1ll * a * b + (i - 1) > 2 * (i - 1)) {
                    sum -= 1ll * a * b;
                    mp.erase(prev(mp.end()));
                }
                else {
                    ll diff = sum + (i - 1) - 2 * (i - 1);
                    ll r = (diff - 1) / a;
 
                    sum -= 1ll * a * r;
                    mp[a] -= r;
                    break;
                }
            }
        }
 
        if (sum + (i - 1) > 2 * (i - 1)) {
            if (prev(mp.end())->first >= f) {
                auto [a, b] = *prev(mp.end());
 
                sum -= a;
                if (--mp[a] == 0)
                    mp.erase(prev(mp.end()));
                
                sum += f;
                mp[f]++;
            }
        }
        else {
            sum += f;
            mp[f]++;
        }
    }
    for (auto [a, b] : mp)
        ans -= b;
 
    cout << ans;
}

• Subtask 1: 8 / 8
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 25 / 25
• Subtask 5: 27 / 27