Submission #1188899

#	Time	Username	Problem	Language	Result	Execution time	Memory
1188899		imppppp	Flooding Wall (BOI24_wall)	C++20	100 / 100	588 ms	55172 KiB

Main

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <array>
#include <string>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <list>
#include <iterator>
#include <numeric>
#include <complex>
#include <utility>
#include <random>
#include <cassert>
#include <fstream>
using namespace std;
mt19937 rnd(time(nullptr));

/* -------------------- Typedefs -------------------- */

typedef int itn;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef float fl;
typedef long double ld;

/* -------------------- Usings -------------------- */

using vi = vector<int>;
using vll = vector<ll>;
using mii = map<int, int>;
using mll = map<ll, ll>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

/* -------------------- Defines -------------------- */

#define ff first
#define ss second
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define mpr make_pair
#define yes cout<<"Yes\n"
#define no cout<<"No\n"
#define all(x) (x).begin(), (x).end()
#define USACO freopen("feast.in", "r", stdin); freopen("feast.out", "w", stdout);

/* -------------------- Constants -------------------- */

const int dx[8] = { -1, 0, 1, 0, -1, -1, 1, 1 };
const int dy[8] = { 0, -1, 0, 1, -1, 1, -1, 1 };
const int MAX = int(1e9 + 5);
const ll MAXL = ll(2e18) + 5ll;
const ll MOD = ll(1000000007);
const ll MOD2 = ll(998244353);

/* -------------------- Functions -------------------- */

void fastio() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
}

void precision(int x) {
    cout.setf(ios::fixed | ios::showpoint);
    cout.precision(x);
}

ll gcd(ll a, ll b) {
    if (a == 0 || b == 0) return 0;
    while (b) {
        a %= b;
        swap(a, b);
    }
    return a;
}

ll lcm(ll a, ll b) {
    return a / gcd(a, b) * b;
}

ll range_sum(ll a, ll b) {
    if (a > b) return 0ll;
    ll dif = a - 1, cnt = b - a + 1;
    ll ans = ((b - a + 1) * (b - a + 2)) / 2;
    ans += ((b - a + 1) * dif);
    return ans;
}

string dec_to_bin(ll a) {
    string s = "";
    for (ll i = a; i > 0; ) {
        ll k = i % 2;
        i /= 2;
        char c = k + 48;
        s += c;
    }
    if (a == 0) {
        s = "0";
    }
    reverse(all(s));
    return s;
}

ll bin_to_dec(string s) {
    ll num = 0;
    for (int i = 0; i < s.size(); i++) {
        num *= 2ll;
        num += (s[i] - '0');
    }
    return num;
}

ll factorial_by_mod(ll n, ll mod) {
    ll ans = 1;
    ll num;
    for (ll i = 1; i <= n; ++i) {
        num = i % mod;
        ans *= num;
        ans %= mod;
    }
    return ans;
}

bool isPrime(ll a) {
    if (a == 1) return false;
    for (ll i = 2; i * i <= a; i++) {
        if (a % i == 0) return false;
    }
    return true;
}

ll binpow(ll a, ll b) {
    if (!a) return 0;
    ll ans = 1;
    while (b) {
        if (b & 1) {
            ans *= a;
        }
        b >>= 1;
        a *= a;
    }
    return ans;
}

ll binpow_by_mod(ll a, ll b, ll mod) {
    if (!a) return 0;
    ll ans = 1;
    while (b) {
        if (b & 1) {
            ans *= a;
            ans %= mod;
        }
        b >>= 1;
        a *= a;
        a %= mod;
    }
    return ans;
}

/* -------------------- Solution -------------------- */

const int INV2 = (MOD + 1) / 2;            

struct SegTree {
    struct Node { int prod, sum; };           
    int n;
    vector<Node> st;
    SegTree(int N, int initVal = 0) : n(N), st(4 * N) {
        build(1, 0, n - 1, initVal);
    }
    static Node merge(const Node& L, const Node& R) {
        Node res;
        res.prod = int((1LL * L.prod * R.prod) % MOD);
        res.sum = (L.sum + 1LL * L.prod * R.sum) % MOD;
        return res;
    }
    void build(int p, int l, int r, int val) {
        if (l == r) { st[p] = { val, val }; return; }
        int m = (l + r) >> 1;
        build(p << 1, l, m, val);
        build(p << 1 | 1, m + 1, r, val);
        st[p] = merge(st[p << 1], st[p << 1 | 1]);
    }
    void update(int idx, int val) { update(1, 0, n - 1, idx, val); }
    void update(int p, int l, int r, int idx, int val) {
        if (l == r) { st[p] = { val, val }; return; }
        int m = (l + r) >> 1;
        if (idx <= m) update(p << 1, l, m, idx, val);
        else          update(p << 1 | 1, m + 1, r, idx, val);
        st[p] = merge(st[p << 1], st[p << 1 | 1]);
    }
    int prod() const { return st[1].prod; }
    int sum()  const { return st[1].sum; }
};

/* ---------- fast exponentiation ---------- */
long long mod_pow(long long a, long long e = 0, long long m = MOD) {
    long long res = 1;
    while (e) {
        if (e & 1) res = res * a % m;
        a = a * a % m;
        e >>= 1;
    }
    return res;
}

struct Event {
    long long h;        
    int idx;              
    int val;              
    bool operator<(const Event& o) const { return h < o.h; }
};

void slv() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N;
    cin >> N;
    vector<long long> a(N), b(N);
    for (auto& x : a) cin >> x;
    for (auto& x : b) cin >> x;

    vector<Event> ev;
    ev.reserve(2 * N);
    for (int i = 0; i < N; ++i) {
        long long mn = min(a[i], b[i]);
        long long mx = max(a[i], b[i]);
        ev.push_back({ mn + 1, i, INV2 });
        ev.push_back({ mx + 1, i, 1 });
    }
    sort(ev.begin(), ev.end());
    SegTree st(N, 0), stR(N, 0);

    long long prevH = 1;         
    long long answer = 0;       
    size_t pos = 0;
    const int Nmod = N % MOD;

    while (pos < ev.size()) {
        long long h = ev[pos].h;
        long long len = h - prevH;             
        if (len) {
            int sumPref = st.sum();
            int sumSuf = stR.sum();
            int prodTot = st.prod();            
            int S = (((Nmod - sumPref - sumSuf) % MOD + MOD) % MOD
                + int(1LL * Nmod * prodTot % MOD)) % MOD;
            answer = (answer + (len % MOD) * 1LL % MOD * S) % MOD;
        }
        while (pos < ev.size() && ev[pos].h == h) {
            int idx = ev[pos].idx;
            int val = ev[pos].val;
            st.update(idx, val);
            stR.update(N - 1 - idx, val);
            ++pos;
        }
        prevH = h;
    }

    long long sumHeights = 0;
    for (int i = 0; i < N; ++i)
        sumHeights = (sumHeights + (a[i] + b[i]) % MOD) % MOD;
    sumHeights = sumHeights * 1LL * INV2 % MOD;

    long long expectedWater = (answer - sumHeights + MOD) % MOD;
    long long result = expectedWater * mod_pow(2, N) % MOD;

    cout << result << '\n';
}

void cs() {
    int tstc = 1;
    //cin >> tstc;
    while (tstc--) {
        slv();
    }
}

void precalc() {
    return;
}

int main() {
    fastio();
    precalc();
    //precision(0);
    cs();
    return 0;
}

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