Submission #1235196

#	Time	Username	Problem	Language	Result	Execution time	Memory
1235196		lrnnz	Split the Attractions (IOI19_split)	C++20	100 / 100	71 ms	18244 KiB

split

#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <queue>
#include "split.h"
using namespace std;

#define all(a) (a).begin(), (a).end()
#define ll long long
#define ld long double
#define ui uint64_t
#define cont(set, element) ((set).find(element) != (set).end())

#define chmin(x, y) (x = min(x, y))
#define chmax(x, y) (x = max(x, y))

/********* DEBUG *********/

template <typename T>
void outvec(const vector<T>& Z){
    for (const T& x : Z)
    cout << x << ' ';
    cout << "\n";
}
void printVariable(const any& var) {
    if (!var.has_value()) {
        cout << "null";
        return;
    }

    if (var.type() == typeid(int)) {
        cout << any_cast<int>(var);
    } else if (var.type() == typeid(double)) {
        cout << any_cast<double>(var);
    } else if (var.type() == typeid(float)) {
        cout << any_cast<float>(var);
    } else if (var.type() == typeid(char)) {
        cout << any_cast<char>(var);
    } else if (var.type() == typeid(bool)) {
        cout << (any_cast<bool>(var) ? "true" : "false");
    } else if (var.type() == typeid(string)) {
        cout << any_cast<string>(var);
    } else if (var.type() == typeid(const char*)) {
        cout << any_cast<const char*>(var);
    } else if (var.type() == typeid(long long)) {
        cout << any_cast<long long>(var);
    } else {
        cout << "[unknown type]";
    }
}

template<typename... Args>
void outval(Args... args) {
    vector<any> variables = {args...};
    
    for (size_t i = 0; i < variables.size(); ++i) {
        printVariable(variables[i]);
        if (i != variables.size() - 1) {
            cout << " ";
        }
    }
    cout << "\n";
}

#define sp << " " <<
#define fi first
#define se second

/********* DEBUG *********/

const ll MOD = 1e9+7;
const ll MOD2 = 998244353;
const ll inf = 1e18;
const ll mxN = 100005;

int timer;
vector<int> low(mxN), seen(mxN), sz(mxN);
vector<vector<int>> adj(mxN);

void dfs(int u, int p = -1){
    low[u] = seen[u] = ++timer;
    sz[u] = 1;

    for (auto &v : adj[u]){
        if (!seen[v]){
            dfs(v, u);
            chmin(low[u], low[v]);
            sz[u] += sz[v];
        }
        else if (v != p){
            chmin(low[u], seen[v]);
        }
    }
}

vector<int> find_split(int n, int a, int b, int c, vector<int> p, vector<int> q) {
    adj.assign(n, vector<int>());
    seen.assign(n, 0);
    timer = 0;

    for (int i = 0; i < p.size(); i++){
        adj[p[i]].push_back(q[i]);
        adj[q[i]].push_back(p[i]);
    }
    
    vector<pair<ll,ll>> labels = {{a, 1}, {b, 2}, {c, 3}};
    sort(all(labels));

    dfs(0);
    for (int i = 1; i < n; i++){
        // check if we're smallest possible centroid with child size >= a
        bool ok = sz[i] >= labels[0].first;
        for (auto &v : adj[i])
            if (seen[v] > seen[i]){
                ok &= (sz[v] < labels[0].first);
            }

        if (!ok)
            continue;
                    
        // try to make smallest a size component
        ll cnt = sz[i];
        vector<ll> out;
        for (auto &v : adj[i]){
            // must not be a bridge
            if (low[v] < seen[i] && seen[i] < seen[v] && cnt - sz[v] >= labels[0].first){
                out.push_back(v);
                cnt -= sz[v];
            }
        }

        // not possible
        if (n - cnt < labels[0].first)
            continue;

        // possible, now color
        if (cnt > n-cnt)
            swap(labels[0], labels[1]);

        vector<bool> vis(n);
        for (auto &x : out)
            vis[x] = true;
        
        vector<int> ans(n, labels[2].second);
        queue<int> q;

        q.push(i);
        vis[i] = true;
        while (q.size() && labels[0].first--){
            ll nd = q.front(); q.pop();
            ans[nd] = labels[0].second;

            for (auto &v : adj[nd]){
                if (!vis[v] && seen[v] > seen[nd]){
                    vis[v] = true;
                    q.push(v);
                }
            }
        }

        while (q.size())
            q.pop();

        for (int j = 0; j < n; j++)
            vis[j] = false;

        q.push(0);
        vis[0] = true;

        while (q.size() && labels[1].first--){
            ll nd = q.front(); q.pop();
            ans[nd] = labels[1].second;
            
            for (auto &v : adj[nd]){
                if (!vis[v] && ans[v] != labels[0].second){
                    vis[v] = true;
                    q.push(v);
                }
            }
        }

        return ans;
    }

    return vector<int>(n);
}

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 22 / 22
• Subtask 4: 24 / 24
• Subtask 5: 36 / 36