Submission #1231102

#	Time	Username	Problem	Language	Result	Execution time	Memory
1231102		BigBadBully	Sphinx's Riddle (IOI24_sphinx)	C++20	18 / 100	598 ms	1464 KiB

sphinx

#include "sphinx.h"
#include <bits/stdc++.h>
using namespace std;
//////////////////////////////////////////////////////////////////
vector<int> find_colours(int N, vector<int> X, vector<int> Y)
{
    auto n = N, m = (int)X.size();
    auto x = X, y = Y;
    vector<int> col(n, 0);
    for (int i = 0; i < n; i++)col[i] = i;
    vector<vector<int>> graph(n);
    for (int i = 0; i < m; i++)
        graph[x[i]].push_back(y[i]),
            graph[y[i]].push_back(x[i]);
    function<int(int)> fnd = [&](int x)
    {
        if (col[x]==x)return x;
        return col[x] = fnd(col[x]);
    };
    auto povezan = [&](vector<int> tuff, int idx)
    {
        vector<int> salji(n, n);
        for (int i : tuff)
            salji[i] = -1;
        vector<bool> vis(n,0);
        function<void(int)> dfs = [&](int cur)
        {
            if (vis[cur] || salji[cur] != n)
                return;
            vis[cur] = 1;
            for (int a : graph[cur])
                dfs(a);
        };
        salji[idx] = -1;
        set<int> dif;
        for (int i : tuff)
            dif.insert(fnd(col[i]));
        int comps = dif.size();
        for (int i = 0; i < n; i++)
            if (!vis[i] && salji[i] == n)
            {
                comps++;
                dfs(i);
            }
        return perform_experiment(salji) <= comps;
    };
    
    vector<int> pref;
    pref.push_back(0);
    for (int i = 1; i < n; i++)
    {
        if (povezan(pref,i))
        {
            set<int> used;
            vector<int> space;
            for (int a : graph[i])
                if (a < i && used.count(fnd(col[a]))==0)
                    space.push_back(a),used.insert(col[a]);
            int k = space.size();
            auto fnd_next = [&](int cur)
            {
                int bg = lower_bound(space.begin(),space.end(),cur)-space.begin();
                int l = bg;
                int r = k; 
                auto check = [&](int bnd)
                {
                    if (bnd==k)return true;
                    vector<int> src;
                    for (int j = bg; j <= bnd; j++)
                        src.push_back(space[j]);
                    return povezan(src,i);
                };
                while(r-l)
                {
                    int mid = l+r>>1;
                    if (check(mid))
                        r = mid;
                    else
                        l = mid+1;
                }
                return l;
            };
            int cur = fnd_next(0);
            while(cur < k)
            {
                col[fnd(space[cur])] = i;
                cur = fnd_next(space[cur]+1);
            }
        }
        pref.push_back(i);
    }
    for (int i = 0; i < n; i++)
        col[i] = fnd(i);

    return col;
}
///////////////////////////////////////////////////////////////////

• Subtask 0: 0 / 0
• Subtask 1: 1.5 / 3
• Subtask 2: 0 / 7
• Subtask 3: 16.5 / 33
• Subtask 4: 0 / 21
• Subtask 5: 0 / 36