Submission #1221221

#	Time	Username	Problem	Language	Result	Execution time	Memory
1221221		steveonalex	Radio Towers (IOI22_towers)	C++20	100 / 100	497 ms	75488 KiB

towers

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned int ul;
typedef unsigned long long ull;
 
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
 
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(abs(a), abs(b));}
ll lcm(ll a, ll b){return abs(a) / gcd(a, b) * abs(b);}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ull 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());
    }

#include "towers.h"

const int INF = 1e9 + 69;

struct SegmentTree{
    int n;
    vector<pair<int,int>> a;

    SegmentTree(int _n = 0){
        n = _n;
        a.resize(n * 2 + 2, {-INF, -INF});
    }

    void update(int i, int v){
        i += n; a[i] = make_pair(v, i - n);
        while(i > 1){
            i >>= 1;
            a[i] = max(a[i * 2], a[i * 2 + 1]);
        }
    }

    pair<int, int> get(int l, int r){
        l += n; r += n + 1;
        pair<int, int> ans = make_pair(-INF, -INF);
        while(l < r){
            if (l & 1) maximize(ans, a[l++]);
            if (r & 1) maximize(ans, a[--r]);
            l >>= 1; r >>= 1;
        }
        return ans;
    }
};


const int N = MASK(17);

struct Persistent{
    struct Node{
        int child[2];
        int sum;

        Node(){
            memset(child, 0, sizeof child);
            sum = 0;
        }
    };

    static const int L = 1, R = N;
    vector<Node> a;
    vector<int> root_stack;

    void add_node(int &x){
        x = a.size();
        a.emplace_back();
    }

    Persistent(){
        a.emplace_back();
        a.emplace_back();
        root_stack.push_back(1);
    }

    int get_cur_version(){
        return root_stack.size() - 1;
    }

    void update(int i, int v, int l, int r, int prev_id, int id){
        a[id] = a[prev_id];
        a[id].sum += v;
        if (l == r) return;

        int mid = (l + r) >> 1;
        if (i <= mid){
            add_node(a[id].child[0]);
            update(i, v, l, mid, a[prev_id].child[0], a[id].child[0]);
        }
        else{
            add_node(a[id].child[1]);
            update(i, v, mid + 1, r, a[prev_id].child[1], a[id].child[1]);
        }
    }

    void update(int i, int v){
        int prev_id = root_stack.back();
        int id; add_node(id);
        root_stack.push_back(id);

        update(i, v, L, R, prev_id, id);
    }

    int get(int u, int v, int l, int r, int id){
        if (u <= l && r <= v) return a[id].sum;
        int mid = (l + r) >> 1;
        int ans = 0;
        if (u <= mid) ans += get(u, v, l, mid, a[id].child[0]);
        if (v > mid) ans += get(u, v, mid+1, r, a[id].child[1]);
        return ans;
    }

    int get(int l, int r, int version){
        return get(l, r, L, R, root_stack[version]);
    }


    int walk_left(int i, int l, int r, int id){
        if (r < i) return -1;
        if (a[id].sum == 0) return -1;
        if (l == r) return l;
        int mid = (l + r) >> 1;
        int left = walk_left(i, l, mid, a[id].child[0]);
        if (left != -1) return left;
        return walk_left(i, mid+1, r, a[id].child[1]);
    }

    int walk_left(int i, int version){
        return walk_left(i, L, R, root_stack[version]);
    }


    int walk_right(int i, int l, int r, int id){
        if (l > i) return -1;
        if (a[id].sum == 0) return -1;
        if (l == r) return l;
        int mid = (l + r) >> 1;
        int right = walk_right(i, mid+1, r, a[id].child[1]);
        if (right != -1) return right;
        return walk_right(i, l, mid, a[id].child[0]);
    }

    int walk_right(int i, int version){
        return walk_right(i, L, R, root_stack[version]);
    }
};


int n;
vector<int> a;
SegmentTree st1, st2;
vector<pair<int, int>> subtract_op, plus_op;
vector<int> X;
vector<pair<int,int>> packets[N * 4];
Persistent pst;
int version_at[N * 4];

void dnc(int l, int r){
    if (l > r) return;
    int mid = st1.get(l, r).second;
    dnc(l, mid-1);
    dnc(mid+1, r);

    int cur_ma = st1.get(l, r).first;
    if (mid > l){
        int left_ma = st1.get(l, mid-1).first;
        int left_mi = -st2.get(l, mid-1).first;
        int left_pos = st2.get(l, mid-1).second;

        plus_op.push_back(make_pair(left_ma - left_mi + 1, left_pos));
        subtract_op.push_back(make_pair(cur_ma - left_mi + 1, left_pos));
    }   
    if (mid < r){
        int right_ma = st1.get(mid+1, r).first;
        int right_mi = -st2.get(mid+1, r).first;
        int right_pos = st2.get(mid+1, r).second;

        plus_op.push_back(make_pair(right_ma - right_mi + 1, right_pos));
        subtract_op.push_back(make_pair(cur_ma - right_mi + 1, right_pos));
    }

}

void init(int N, vector<int> H) {
    H.insert(H.begin(), 0);
    n = N; a = H;
    st1 = SegmentTree(n), st2 = SegmentTree(n);
    for(int i = 1; i <= n; ++i){
        st1.update(i, a[i]);
        st2.update(i, -a[i]);
    }

    dnc(1, n);

    for(pair<int, int> i: subtract_op) X.push_back(i.first);
    for(pair<int, int> i: plus_op) X.push_back(i.first);

    X.push_back(0);
    remove_dup(X);

    for(pair<int, int> i: subtract_op){
        i.first = lower_bound(ALL(X), i.first) - X.begin();
        packets[i.first].push_back(make_pair(i.second, -1));
    }
    for(pair<int, int> i: plus_op){
        i.first = lower_bound(ALL(X), i.first) - X.begin();
        packets[i.first].push_back(make_pair(i.second, 1));
    }

    pst.a.reserve(1e7);
    for(int i = 0; i < (int) X.size(); ++i){
        for(pair<int, int> j: packets[i]){
            pst.update(j.first, j.second);
        }
        version_at[i] = pst.get_cur_version();
    }
}


int max_towers(int l, int r, int d) {
    l++; r++;
    int idx = upper_bound(ALL(X), d) - X.begin() - 1;
    int ans = pst.get(l, r, version_at[idx]);
    if (ans == 0){
        pair<int, int> cur = st1.get(l, r);
        int mid = cur.second;
        if (mid > l){
            int bruh = -st2.get(l, mid-1).first;
            if (cur.first - bruh >= d) ans++;
        }
        if (mid < r){
            int bruh = -st2.get(mid+1, r).first;
            if (cur.first - bruh >= d) ans++;
        }
        maximize(ans, 1);
    }
    else{
        int le = pst.walk_left(l, version_at[idx]);
        int ri = pst.walk_right(r, version_at[idx]);
        if (l < le){
            pair<int, int> cur = st1.get(l, le - 1);
            if (cur.second > l){
                int bruh = -st2.get(l, cur.second - 1).first;
                if (cur.first - max(bruh, a[le]) >= d) ans++;
            }
        }
        if (ri < r){
            pair<int, int> cur = st1.get(ri+1, r);
            if (cur.second < r){
                int bruh = -st2.get(cur.second+1, r).first;
                if (cur.first - max(bruh, a[ri]) >= d) ans++;
            }
        }
    }
    return ans;
}

• Subtask 1: 4 / 4
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 14 / 14
• Subtask 5: 17 / 17
• Subtask 6: 19 / 19
• Subtask 7: 23 / 23