Submission #1116548

#	Time	Username	Problem	Language	Result	Execution time	Memory
1116548		Pekiban	Flooding Wall (BOI24_wall)	C++17	70 / 100	2254 ms	22460 KiB

Main

#include <bits/stdc++.h>
 
using namespace std;
using ll = long long;
#define pb push_back
 
const ll N = 5e5, M = 2e4 + 3, MOD = 1e9 + 7;
const ll FIX = MOD * MOD * 4;
ll P[N];
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    P[0] = 1;
    for (int i = 1; i < N; ++i) P[i] = (P[i-1] * 2) % MOD;
    int n;
    cin >> n;
    int a[n+1], b[n+1];
    vector<int> v;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        v.pb(a[i]);
    }
    for (int i = 1; i <= n; ++i) {
        cin >> b[i];
        v.pb(b[i]);
        if (b[i] < a[i])    swap(a[i], b[i]);
    }
    if (n <= 1e4+2) {
        ll X[M], Y[M];
        sort(v.begin(), v.end());
        v.erase(unique(v.begin(), v.end()), v.end());
        auto findx = [&](int x) {
            return lower_bound(v.begin(), v.end(), x) - v.begin();
        };
        for (int i = 1; i <= n; ++i) a[i] = findx(a[i]), b[i] = findx(b[i]);
        ll ans = 0;
        for (int i = 1; i <= n; ++i) {
            fill(X, X+M, 0);
            fill(Y, Y+M, 0);
            int Xmx = 0, Ymx = 0;
            for (int j = 1; j < i; ++j) Xmx = max(Xmx, a[j]), X[b[j]]++;
            for (int j = 0; j < M; ++j) {
                if (j != M-1)   X[j+1] += X[j];
                X[j] = (Xmx > j ? 0 : P[X[j]]);
            }
            for (int j = i+1; j <= n; ++j) Ymx = max(Ymx, a[j]), Y[b[j]]++;
            for (int j = 0; j < M; ++j) {
                if (j != M-1)   Y[j+1] += Y[j];
                Y[j] = (Ymx > j ? 0 : P[Y[j]]);
            }
            for (int j = a[i] + 1; j < M; ++j) {
                ans += (v[j] - v[a[i]]) * (((X[j] - X[j-1]) * (Y[M-1] - Y[j-1]) + (Y[j] - Y[j-1]) * (X[M-1] - X[j-1]) - (X[j] - X[j-1]) * (Y[j] - Y[j-1]) + FIX) % MOD);
                ans %= MOD;
            }
            for (int j = b[i] + 1; j < M; ++j) {
                ans += (v[j] - v[b[i]]) * (((X[j] - X[j-1]) * (Y[M-1] - Y[j-1]) + (Y[j] - Y[j-1]) * (X[M-1] - X[j-1]) - (X[j] - X[j-1]) * (Y[j] - Y[j-1]) + FIX) % MOD);
                ans %= MOD;
            }
        }
        cout << ans << '\n';
    }
    else {
        ll ans = 0;
        for (int i = 1; i <= n; ++i) {
            ans += (P[i-1] - 1) * (P[n-i] - 1) % MOD;
            ans %= MOD;
        }
        cout << ans << '\n';    
    }
} 

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