Submission #998477

#	Time	Username	Problem	Language	Result	Execution time	Memory
998477		steveonalex	Flooding Wall (BOI24_wall)	C++17	58 / 100	5088 ms	23800 KiB

Main

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
#define block_of_code if(true)
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }


 
const int MOD = 1e9 + 7;
struct Modular{
    ll x;
    Modular(ll _x = 0){x = _x;}
    Modular& operator += (Modular y){
        x += y.x;
        if (x >= MOD) x -= MOD;
        return *this;
    }
    Modular operator + (Modular y) {
        Modular tmp = *this;
        return tmp += y;
    }
 
    Modular& operator -= (Modular y){
        x -= y.x;
        if (x < 0) x += MOD;
        return *this;
    }
    Modular operator - (Modular y) {
        Modular tmp = *this;
        return tmp -= y;
    }
 
    Modular& operator *= (Modular y){
        x *= y.x;
        if (x >= MOD) x %= MOD;
        return *this;
    }
    Modular operator * (Modular y) {
        Modular tmp = *this;
        return tmp *= y;
    }
 
    // use at your own risk
    bool operator == (Modular y){
        return x == y.x;
    }
    bool operator != (Modular y){
        return x != y.x;
    }
};
ostream& operator << (ostream& out, Modular x){
    out << x.x;
    return out;
}

const int N = 5e5 + 69;
array<int, 2> a[N];
array<Modular, 2> pref[N], suff[N];
Modular p2[N];

int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int n; cin >> n;
    for(int j = 0; j<=1; ++j)
    for(int i = 0; i<n; ++i) cin >> a[i][j];
    for(int i = 0; i<n; ++i) sort(ALL(a[i]));

    p2[0] = 1;
    for(int i = 1; i<N; ++i) p2[i] = p2[i-1] * 2;

    Modular ans = 0;

    for(int i= 0; i<n; ++i){
        for(int u: a[i]) ans -= p2[n-1] * u;
    }
    for(int iteration = 0; iteration <= 1; ++iteration){
        for(int i = 0; i<n; ++i){
            for(int u: a[i]){
                Modular cu = 1;
                for(int j = 0; j< i; ++j) {
                    int cnt=  0;
                    for(int v: a[j]) if (v < u) cnt++;
                    cu *= cnt;
                    if (cu == 0) break;
                }
                if (cu == 0) continue;
                for(int j = i + 1; j<n; ++j){
                    Modular sum = (Modular) u * (j - i);
                    for(int v: a[j]) if (v > u) ans += sum * cu * p2[n-1-j];
                    
                    int cnt=  0;
                    for(int v: a[j]) if (v <= u) cnt++;
                    cu *= cnt;
                    if (cu == 0) break;
                }
            }
        }
        reverse(a, a + n);
    }

    for(int i =0; i<n; ++i){
        for(int u = 0; u<=1; ++u){
            Modular cur = 1;
            for(int j = 0; j<i; ++j) {
                int cnt = 0;
                for(int v: a[j]) cnt += v < a[i][u];
                cur *= cnt;
            }
            pref[i][u] = cur;


            cur = 1;
            for(int j = i+1; j<n; ++j) {
                int cnt = 0;
                for(int v: a[j]) cnt += v < a[i][u];
                cur *= cnt;
            }
            suff[i][u] = cur;
        }
    }

    for(int i = 0; i<n; ++i) {
        for(int u = 0; u <= 1; ++u) ans += pref[i][u] * suff[i][u] * a[i][u];
    }
    for(int i = 0; i<n; ++i) for(int u = 0; u <= 1; ++u){
        Modular mul = 1;
        for(int j = i + 1; j<n; ++j){
            for(int v = 0; v <= 1; ++v) if (a[i][u] == a[j][v]){
                ans += pref[i][u] * suff[j][v] * mul * a[i][u] * (j - i + 1);
            }

            int cnt= 0;
            for(int v: a[j]) cnt += v <= a[i][u];
            mul *= cnt; 
        }
    }



    cout << ans << "\n";


    return 0;
}

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