Submission #750915

#	Time	Username	Problem	Language	Result	Execution time	Memory
750915		drdilyor	Drawing (CEOI22_drawing)	C++17	15 / 100	1576 ms	18292 KiB

Main

#include<bits/stdc++.h>

using namespace std;
using ll = long long;
const int inf = 1e9;
const ll infl = 1e18;
mt19937 rng;

using pt = pair<int,int>;
bool ccw(pt A, pt B, pt C) {
    return ll(C.second-A.second) * (B.first-A.first) > ll(B.second-A.second) * (C.first-A.first);
}
bool intersect(pt A, pt B, pt C, pt D) {
    return ccw(A, C, D) != ccw(B, C, D) && ccw(A, B, C) != ccw(A, B, D);
}

int main() {

    int n;
    cin >> n;

    vector<vector<int>> adj(n);
    vector<pair<int,int>> pts(n);
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        u--;v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    map<pair<int,int>, int> ix;
    for (auto& [x, y] : pts)
        cin >> x >> y;
    for (int i = 0; i < n; i++)
        ix[pts[i]]= i;

    int r = 0;
    for (; r < n; r++)
        if (adj[r].size() < 3) break;

    vector<int> res(n, -1);
    vector<int> subs(n, 1);
    auto dfs_sz = [&](auto& dfs_sz, int i, int p=-1)->void {
        for (int e : adj[i]) if (e != p) {
            dfs_sz(dfs_sz, e, i);
            subs[i] += subs[e];
        }
    };
    dfs_sz(dfs_sz, r);

    auto dfs = [&](auto& dfs, vector<pair<int,int>>::iterator p1, vector<pair<int,int>>::iterator p2, int i, int p =-1)->void {
        vector<int> ch;
        for (int e : adj[i]) {
            if (e != p) ch.push_back(e);
        }
        if (ch.empty()) {
            assert(p1 == p2);
            return;
        }
        if (ch.size() == 1) {
            res[ch[0]] = ix[*--p2];
            dfs(dfs, p1, p2, ch[0], i);
        } else {
            sort(p1, p2, [](auto& p, auto& q)->bool {
                return (ll)p.second * q.first > (ll) q.second * p.first;
            });
            assert(p2 - p1 == subs[ch[0]] + subs[ch[1]]);
            auto q1 = p1 + subs[ch[0]];
            auto q2 = p2;
            sort(p1, p2, greater());
            sort(q1, q2, greater());
            p2 = q1;
            res[ch[0]] = ix[*--p2];
            res[ch[1]] = ix[*--q2];
            dfs(dfs, p1, p2, ch[0], i);
            dfs(dfs, q1, q2, ch[1], i);
        }
    };

    sort(pts.begin(), pts.end(), greater());
    res[r] = ix[pts.back()];
    pts.pop_back();
    dfs(dfs, pts.begin(), pts.end(), r);

    vector<int> byp(n);
    for (int i = 0; i < n; i++)
        assert(res[i] >= 0),
        byp[res[i]] = i;
    for (int i : byp) {
        cout << i+1 << ' ';
    }
    cout << '\n';

    return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 15 / 15
• Subtask 3: 0 / 15
• Subtask 4: 0 / 35
• Subtask 5: 0 / 25