Submission #1234895

#	Time	Username	Problem	Language	Result	Execution time	Memory
1234895		Hanksburger	Permutation Game (APIO25_permgame)	C++20	6 / 100	0 ms	328 KiB

permgame

#include "permgame.h"
#include <bits/stdc++.h>
using namespace std;
vector<vector<int> > perm;
vector<int> adj[405], vec;
int ans, initans;
void computePerm(vector<int> P)
{
    int visited[405]={};
    ans=0;
    perm.clear();
    for (int i=0; i<P.size(); i++)
    {
        if (visited[i])
            continue;
        vector<int> tmp;
        int cur=i;
        while (!visited[cur])
        {
            tmp.push_back(cur);
            visited[cur]=1;
            cur=P[cur];
        }
        if (tmp.size()==1)
            ans++;
        else
            perm.push_back(tmp);
    }
}
int Alice(int M, int E, vector<int> U, vector<int> V, int N, vector<int> P)
{
    for (int i=0; i<E; i++)
    {
        adj[U[i]].push_back(V[i]);
        adj[V[i]].push_back(U[i]);
    }
    computePerm(P);
    initans=ans;
    for (int i=0; i<M; i++)
        if (adj[i].size()>=3)
            return ans;
    if (E<M)
    {
        for (int i=0; i<M; i++)
        {
            if (adj[i].size()==1)
            {
                vec.push_back(i);
                break;
            }
        }
        for (int i=1; i<M; i++)
        {
            if (i==1)
                vec.push_back(adj[vec[i-1]][0]);
            else
            {
                int pre=vec[i-2];
                if (adj[vec[i-1]][0]==pre)
                    vec.push_back(adj[vec[i-1]][1]);
                else
                    vec.push_back(adj[vec[i-1]][0]);
            }
        }
        while (1)
        {
            int updated=0, sum=0;
            for (int i=0; i<perm.size(); i++)
            {
                if (perm[i].size()>=M)
                {
                    updated=1;
                    vector<int> tmp(M);
                    for (int j=0; j<M; j++)
                        tmp[vec[j]]=perm[0][j];
                    int edge=Bob(tmp);
                    swap(P[tmp[U[edge]]], P[tmp[V[edge]]]);
                    computePerm(P);
                    break;
                }
                sum+=perm[i].size();
                if (sum>=M)
                {
                    updated=1;
                    vector<int> tmp(M);
                    int cnt=0;
                    for (int j=0; j<=i; j++)
                    {
                        for (int x:perm[j])
                        {
                            tmp[vec[cnt]]=x;
                            cnt++;
                            if (cnt==M)
                                break;
                        }
                        if (cnt==M)
                            break;
                    }
                    int edge=Bob(tmp);
                    swap(P[tmp[U[edge]]], P[tmp[V[edge]]]);
                    computePerm(P);
                    break;
                }
            }
            if (!updated)
                break;
        }
        return max(initans, N-M+1);
    }
}

Compilation message (stderr)

permgame.cpp: In function 'int Alice(int, int, std::vector<int>, std::vector<int>, int, std::vector<int>)':
permgame.cpp:110:1: warning: control reaches end of non-void function [-Wreturn-type]
  110 | }
      | ^

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