Submission #1206914

#	Time	Username	Problem	Language	Result	Execution time	Memory
1206914		thangdzwinioi	Real Mountains (CCO23_day1problem2)	C++20	25 / 25	1018 ms	164736 KiB

Main

#include <bits/stdc++.h>

using namespace std;

const int MAX = 1e6 + 5;
const int mod = 1e6 + 3;

int n, h[MAX], pref[MAX], suff[MAX], tar[MAX];
vector <int> ord;

int fd(int value){
    return lower_bound(ord.begin(), ord.end(), value) - ord.begin();
}

int sr(int l, int r){
    return 1ll * (l + r) * (r - l + 1) / 2 % mod;
}

int mul(int a, int b){
    return 1ll * a * b % mod;
}

void add(int &a, int b){
    a += b;
    if (a >= mod) a -= mod;
}

int cnt[MAX], siz;

pair <int, int> st[MAX << 2];
pair <int, int> inf = {1e9, 0};

pair <int, int> operator + (const pair <int, int> &A, const pair <int, int> &B){
    return make_pair(min(A.first, B.first), max(A.second, B.second));
}

void update(int u, int v, int val, int s = 1, int l = 1, int r = siz - 1){
    if (u <= l && r <= v){
        st[s] = st[s] + make_pair(val, val);
        return;
    }

    int mid = l + r >> 1;

    if (mid >= u) update(u, v, val, s << 1, l, mid);
    if (mid < v) update(u, v, val, s << 1 | 1, mid + 1, r);
}

pair <int, int> cur[MAX];

void dfs(int s = 1, int l = 1, int r = siz - 1){
    if (l == r) {
        cur[l] = st[s];
        return;
    }

    int mid = l + r >> 1;
    for (int child : {s << 1, s << 1 | 1})
        st[child] = st[child] + st[s];

    dfs(s << 1, l, mid);
    dfs(s << 1 | 1, mid + 1, r);
}

vector <int> pos[MAX];

void process(){
    cin >> n;
    for (int i = 1; i <= n; ++ i) {
        cin >> h[i];
        ord.push_back(h[i]);
    }

    sort(ord.begin(), ord.end());
    ord.erase(unique(ord.begin(), ord.end()), ord.end());
    siz = ord.size();

    if (siz == 1){
        cout << 0;
        return;
    }

    for (int i = 1; i <= n; ++ i)
        pref[i] = max(pref[i - 1], h[i]);
    for (int i = n; i >= 1; -- i)
        suff[i] = max(suff[i + 1], h[i]);

    for (int i = 1; i <= siz * 4; ++ i)
        st[i] = inf;

    int ans = 0;
    for (int i = 1; i <= n; ++ i){
        tar[i] = min(pref[i], suff[i]);
        add(ans, sr(h[i], tar[i] - 1));
        int l = fd(h[i]) + 1, r = fd(tar[i]) + 1;
        pos[l - 1].push_back(i);
        if (l < r){
            cnt[l] ++, cnt[r] --;
            update(l, r - 1, i);
        }
    }

    dfs();

    for (int i = 1; i < siz; ++ i)
        cnt[i] += cnt[i - 1];

    set <int> sf, pf;

    for (int i = siz - 1; i > 0; -- i){
        for (int p : pos[i]){
            pf.insert(p);
            auto curp = pf.upper_bound(p);
            while (curp != pf.end())
                curp = pf.erase(curp);

            sf.insert(p);
            auto curf = sf.lower_bound(p);
            while (curf != sf.begin()){
                curf --;
                curf = sf.erase(curf);
            }
        }

        int dist = ord[i] - ord[i - 1];
        int cost = sr(ord[i - 1] + 1, ord[i]);

        if (cnt[i] == 0) continue;

        int l = *(--pf.upper_bound(cur[i].first));
        int r = *(sf.lower_bound(cur[i].second));

        add(ans, mul(h[l] + h[r], dist));

        if (cnt[i] == 1) continue;
        if (cnt[i] >= 2){
            add(ans, mul(cnt[i] * 2 - 3, cost));
            add(ans, mul(h[*sf.begin()], dist));
        }
    }

    cout << ans;
}

int main(){

    //freopen("chill.inp", "r", stdin);
    //freopen("chill.ans", "w", stdout);

    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    process();
    return 0;
}

• Subtask 1: 3 / 3
• Subtask 2: 3 / 3
• Subtask 3: 3 / 3
• Subtask 4: 3 / 3
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
• Subtask 7: 4 / 4