Submission #1003532

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003532		vjudge1	Flooding Wall (BOI24_wall)	C++17	56 / 100	5056 ms	29780 KiB

Main

#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector,fast-math,inline")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,lzcnt,mmx,abm,avx,avx2,fma")
#include <bits/stdc++.h>
using namespace std;

#define int long long
#define all(x) x.begin(), x.end()

const int N = 5e5, mod = 1e9+7;

int n, a[N], b[N], pre[N], suf[N], pw[N];
vector<pair<int, int>> cp;

signed main() {
  ios::sync_with_stdio(false); cin.tie(nullptr);

  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < n; i++) {
    cin >> b[i];
    if (a[i] > b[i]) swap(a[i], b[i]);
  }

  pw[0] = 1;
  for (int i = 1; i < n; i++) {
    pw[i] = (pw[i-1] << 1) % mod;
  }

    vector<int> u(n*2);
    u.push_back(0);
    for (int i = 0; i < n; i++) {
      u[i*2] = a[i];
      u[i*2 + 1] = b[i];
    }
    sort(all(u));
    u.erase(unique(all(u)), u.end());

    int sz = u.size();
    cp.reserve(sz);
    for (int i = 0; i < sz; i++) {
      cp.push_back(make_pair(u[i], u[i]));

      if (i+1 < sz && u[i]+1 <= u[i+1]-1) cp.push_back(make_pair(u[i]+1, u[i+1]-1));
    }
    sz = cp.size();

    int ans = 0;
    for (int j = 0; j+1 < sz; j++) {
      for (int i = 0; i < n; i++) {
        pre[i] = (i ? pre[i-1] : 1);
        
        if (b[i] <= cp[j].second) {
          pre[i] *= 2;
          pre[i] %= mod;
        }
        else if (a[i] > cp[j].second) pre[i] = 0;
      }
    
      for (int i = n-1; i >= 0; i--) {
        suf[i] = (i+1 < n ? suf[i+1] : 1);
        
        if (b[i] <= cp[j].second) {
          suf[i] *= 2;
          suf[i] %= mod;
        }
        else if (a[i] > cp[j].second) suf[i] = 0;
      }
    
      for (int i = 1; i < n-1; i++) {
        int x = 0;
        
        x += pw[n-1-i] * pre[i-1];
        x %= mod;

        x += pw[i] * suf[i+1];
        x %= mod;

        x = (x - pre[i-1] * suf[i+1] + mod) % mod;

        if (a[i] < cp[j+1].first) {
          ans += (pw[n-1] - x + mod) % mod * (cp[j+1].second-cp[j+1].first+1);
          ans %= mod;
        }

        if (b[i] < cp[j+1].first) {
          ans += (pw[n-1] - x + mod) % mod * (cp[j+1].second-cp[j+1].first+1);
          ans %= mod;
        }
      }
    }

    cout << ans << "\n";
}

• Subtask 1: 8 / 8
• Subtask 2: 17 / 17
• Subtask 3: 19 / 19
• Subtask 4: 0 / 14
• Subtask 5: 12 / 12
• Subtask 6: 0 / 30