Submission #1266709

#	Time	Username	Problem	Language	Result	Execution time	Memory
1266709		abdelhakim	Permutation Game (APIO25_permgame)	C++20	30 / 100	12 ms	328 KiB

permgame

#include "permgame.h"
#include <vector>
#include <utility>
#include <bits/stdc++.h>
#define dbg(x) cerr << #x << ' ' << x << endl;
#define ll long long
#define inf (ll) 1e17
using namespace std;

//         vector<int> t={ind[i],i};
//         int j = Bob(t);
//         std::swap(p[t[u[j]]], p[t[v[j]]]);

vector<bool> vis;
vector<int> ind;
void dfs(ll node, ll par, vector<vector<ll>>& adj)
{
    if(vis[node]) return;
    vis[node]=true;
    ind.push_back(node);
    for (auto &&e : adj[node])
    {
        if(e!=par)
        {
            dfs(e,node,adj);
        }
    }
}
void combine(vector<int>& p, vector<int> v1, vector<int> v2, vector<int>& u, vector<int>& v)
{
    vector<int> t(4);
    t[ind[0]]=v1[0];
    t[ind[1]]=v2[0];
    t[ind[2]]=v1[1];
    t[ind[3]]=v2[1];
    int j = Bob(t);
    std::swap(p[t[u[j]]], p[t[v[j]]]);
}
vector<vector<int>> groups(vector<int>& p)
{
    vector<vector<int>> grps;
    vector<bool> v(p.size(),false);
    for (int i=0;i<p.size();i++)
    {
        if(i!=p[i] && !v[i])
        {
            vector<int> g;
            for (int j=i;true;j=p[j])
            {
                v[j]=1;
                g.push_back(j);
                if(p[j]==i) break;
            }
            grps.push_back(g);
        }
    }
    return grps;
}
int Alice(int m, int e, std::vector<int> u, std::vector<int> v, int n, std::vector<int> p) {
    vector<vector<ll>> adj(m);
    vis.assign(n,0);
    ll curans=0;
    for (int i=0;i<n;i++)
    {
        curans+=p[i]==i;
    }
    for (int i=0;i<e;i++)
    {
        adj[u[i]].push_back(v[i]);
        adj[v[i]].push_back(u[i]);
    }
    for (int i=0;i<m;i++)
    {
        if(adj[i].size() > 2)
        {
            return curans;
        }
    }
    dfs(0,0,adj);
    vis.assign(n,0);
    for (int i=0;i<n;i++)
    {
        if(p[i]!=i && !vis[i])
        {
            vector<int> g;
            for (int j=i;true;j=p[j])
            {
                vis[j]=true;
                g.push_back(j);
                if(p[j]==i) break;
            }
            while(g.size() > 4)
            {
                vector<int> t(4);
                t[ind[0]]=g[0];
                t[ind[1]]=g[1];
                t[ind[2]]=g[3];
                t[ind[3]]=g[4];
                int j = Bob(t);
                std::swap(p[t[u[j]]], p[t[v[j]]]);
                g.clear();
                for (int j=i;true;j=p[j])
                {
                    g.push_back(j);
                    if(p[j]==i) break;
                }
            }
        }
    }
    vis.assign(n,0);
    while(true)
    {
        bool salina=true;
        vector<vector<int>> grps=groups(p);
        for (auto &&g : grps)
        {
            while(g.size() > 4)
            {
                salina=false;
                ll indx=g[0];
                vector<int> t(4);
                t[ind[0]]=g[0];
                t[ind[1]]=g[1];
                t[ind[2]]=g[3];
                t[ind[3]]=g[4];
                int j = Bob(t);
                std::swap(p[t[u[j]]], p[t[v[j]]]);
                g.clear();
                for (int j=indx;true;j=p[j])
                {
                    g.push_back(j);
                    if(p[j]==indx) break;
                }
            }
        }
        grps=groups(p);
        for (auto &&g : grps)
        {
            if(g.size()==4)
            {
                salina=false;
                vector<int> t(4);
                t[ind[0]]=g[0];
                t[ind[1]]=g[1];
                t[ind[2]]=g[2];
                t[ind[3]]=g[3];
                int j = Bob(t);
                std::swap(p[t[u[j]]], p[t[v[j]]]);
            }
        }
        grps=groups(p);
        sort(grps.begin(), grps.end(),[](vector<int>& g1, vector<int>& g2){return g1.size() < g2.size();});
        for (int i=1;i<grps.size();i++)
        {
            if(grps[i].size() == grps[i-1].size())
            {
                salina=false;
                combine(p,{grps[i][0],grps[i][1]},{grps[i-1][0],grps[i-1][1]},u,v);
                break;
            }
        }
        if(salina)break;
    }
    ll cnt=0;
    for (int i=0;i<n;i++)
    {
        cnt+=p[i]==i;
    }
    return cnt;
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 6
• Subtask 2: 6 / 6
• Subtask 3: 0 / 10
• Subtask 4: 0 / 24
• Subtask 5: 24 / 24
• Subtask 6: 0 / 30