Submission #919913

#	Time	Username	Problem	Language	Result	Execution time	Memory
919913		CyberCow	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	28 ms	5584 KiB

fancyfence

#include <random>
#include <algorithm>
#include <bitset>
#include <chrono>
#include <cmath>
#include <deque>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include <chrono>
#define m_p make_pair
#define all(x) (x).begin(),(x).end()
#define sz(x) ((x).size())
typedef long long ll;
using namespace std;
mt19937 rnd(348502);
const ll N = 2010;
ll mod = 1e9 + 7;

void solve()
{
    ll x, y, a, b;
    int i, n;
    cin >> n;
    vector<pair<ll, ll>> v;
    for ( i = 0; i < n; i++)
    {
        cin >> x;
        v.push_back({ x, 0 });
    }
    for ( i = 0; i < n; i++)
    {
        cin >> x;
        v[i].second = x;
    }
    ll qan = 0, ans = 0;
    stack<pair<ll, ll>> s;
    for ( i = 0; i < n; i++)
    {
        ll ne = 0;
        ans = (ans + (v[i].first * (v[i].first - 1) / 2 + v[i].first) % mod * ((v[i].second * (v[i].second - 1) / 2 + v[i].second) % mod) % mod) % mod;
        while (!s.empty() && s.top().first > v[i].first)
        {
            qan = (mod + (qan - (s.top().first * (s.top().first - 1) / 2+ s.top().first) % mod * s.top().second % mod) % mod) % mod;
            qan = (qan + (v[i].first * (v[i].first - 1) / 2 + v[i].first) % mod * s.top().second) % mod;
            ne = (ne + s.top().second) % mod;
            s.pop();
        }
        ans = (ans + qan * v[i].second) % mod;
        qan = (qan + (v[i].first * (v[i].first - 1) / 2 + v[i].first) % mod * v[i].second % mod) % mod;
        s.push({ v[i].first, (ne + v[i].second) % mod });
    }
    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    ll tt = 1;
    //cout << (mod + -10000010 % mod) % mod;
    //cin >> tt;
    while (tt--) {
        solve();
    }
    return 0;
}

Compilation message (stderr)

fancyfence.cpp: In function 'void solve()':
fancyfence.cpp:31:11: warning: unused variable 'y' [-Wunused-variable]
   31 |     ll x, y, a, b;
      |           ^
fancyfence.cpp:31:14: warning: unused variable 'a' [-Wunused-variable]
   31 |     ll x, y, a, b;
      |              ^
fancyfence.cpp:31:17: warning: unused variable 'b' [-Wunused-variable]
   31 |     ll x, y, a, b;
      |                 ^

• Subtask 1: 0 / 0
• Subtask 2: 12 / 12
• Subtask 3: 13 / 13
• Subtask 4: 15 / 15
• Subtask 5: 15 / 15
• Subtask 6: 18 / 18
• Subtask 7: 27 / 27