Submission #1132876

#	Time	Username	Problem	Language	Result	Execution time	Memory
1132876		turska	Tiles (BOI24_tiles)	C++20	100 / 100	142 ms	17584 KiB

Main

// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;
template <class T>
using indexed_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
/*using ll = __int128;*/
using ll = long long;
using ull = unsigned long long;

using pii = pair<int, int>;
using pll = pair<ll, ll>;

const ll M = 998244353;
/*const ll M = 1e9 + 7;*/

#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define ff first
#define ss second
#define PI 3.141592653589793238462643383279502884L

const ll INFL = 1e18;
const int INF = 1e9;
const int maxN = 1e6+1;

struct edge {
    int l,r;
};
bool operator<(const edge &a, const edge &b) {
    if (a.l==b.l) return a.r < b.r;
    return a.l < b.l;
};

set<edge> st[2]; // l<=r
int cnt_odd = 0;
void insert(edge e, int m) { // edges intersecting wont exists
    auto it = st[m].upper_bound(e);
    int l = e.l, r = e.r;
    if (it!=st[m].end()) {
        if (it->l==e.r) {
            cnt_odd -= (it->r-it->l)%2==1;
            r = it->r;
            st[m].erase(it);
        }
    }
    it = st[m].upper_bound(e);
    if (it!=st[m].begin()) {
        it--;
        if (it->r==e.l) {
            cnt_odd -= (it->r-it->l)%2==1;
            l = it->l;
            st[m].erase(it);
        }
    }
    cnt_odd += (r-l)%2==1;
    st[m].insert({l, r});
};

bool contains(edge e, int m)  {
    auto it = st[m].lower_bound(e);
    if (it==st[m].end() || it->l>=e.r) {
        if (it==st[m].begin()) return false;
        it--;
    }
    return max(it->l, e.l)<min(it->r, e.r);
}

bool remove(edge e, int m) { // false if edge is in 1-m 
    if (contains(e, 1-m)) return false;

    auto it = st[m].lower_bound(e);
    if (it==st[m].end() || it->l>=e.r) it--;
    cnt_odd -= (it->r-it->l)%2==1;

    edge f = *it;
    st[m].erase(it);
    if (f.l < e.l) {
        cnt_odd += (e.l-f.l)%2==1;
        st[m].insert({f.l, e.l});
    }
    if (f.r > e.r) {
        cnt_odd += (f.r-e.r)%2==1;
        st[m].insert({e.r, f.r});
    }
    return true;
}


void solve() {
    int ans = 0;
    map<int, vector<edge>> evt;
    int n, m;
    cin >> n >> m;

    vector<array<int, 2>> points(n);
    for (int i=0; i<n; i++) cin >> points[i][0] >> points[i][1];
    points.push_back(points[0]);
    for (int i=0; i<n; i++) {
        if (points[i][1]==points[i+1][1]) continue;
        int l = min(points[i][1], points[i+1][1]);
        int r = max(points[i][1], points[i+1][1]);
        evt[points[i][0]].push_back({l, r});
    }
    for (auto &[x, edges]: evt) {
        vector<edge> add, del;
        for (auto e: edges) {
            if (contains(e, 0)||contains(e, 1)) del.push_back(e);
            else add.push_back(e);
        }
        if (x%2) {
            if (st[0].empty()) ans = max(ans, x);
            if (st[1].empty()) ans = max(ans, x-1);
        } else {
            if (st[0].empty()) ans = max(ans, x-1);
            if (st[1].empty()) ans = max(ans, x);
        };
        for (auto e: del) {
            if (!remove(e, x%2)) {
                cout << ans << '\n';
                return;
            };
        }
        for (auto e: add) {
            insert(e, x%2);
        }
        if (cnt_odd) break;
    }
    cout << ans << '\n';
};


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout << fixed << setprecision(12);
    int tc = 1;
    /*cin >> tc;*/
    while (tc--) solve();
}

• Subtask 1: 4 / 4
• Subtask 2: 9 / 9
• Subtask 3: 11 / 11
• Subtask 4: 19 / 19
• Subtask 5: 22 / 22
• Subtask 6: 25 / 25
• Subtask 7: 10 / 10