Submission #774118

#	Time	Username	Problem	Language	Result	Execution time	Memory
774118		danikoynov	Game (IOI14_game)	C++14	42 / 100	1078 ms	13800 KiB

game

#include "game.h"
#include <bits/stdc++.h>

using namespace std;

const int maxn = 1510;
int n;

int  used[maxn], in_st[maxn * maxn], in_mst[maxn * maxn];
vector < int > st, mst;
mt19937 rng;

void random_shuffle()
{

    for (int i = 0; i < st.size(); i ++)
    {
        int idx = rng() % (int)(st.size());
        swap(st[i], st[idx]);
    }
}

int par[maxn];
int find_leader(int v)
{
    if (v == par[v])
        return v;
    return (par[v] = find_leader(par[v]));
}

bool unite(int v, int u)
{
    v = find_leader(v);
    u = find_leader(u);
    if (v == u)
        return false;
    par[v] = u;
    return true;
}
void initialize(int N)
{
    n = N;
    for (int i = 0; i < n; i ++)
        for (int j = i + 1; j < n; j ++)
    {
        if (i != j)
        {


                st.push_back(i * n + j), in_st[i * n + j] = 1;
        }
    }

    for (int i = 0; i < n; i ++)
        par[i] = i;
    random_shuffle();
    for (int edge : st)
    {
        int v = edge / n, u = edge % n;
        if (unite(v, u))
        {
            ///cout << v << " : " << u << endl;
            in_st[edge] = 0;
            in_mst[edge] = 1;
            mst.push_back(edge);
        }
    }
    random_shuffle();

}
vector < int > adj[maxn];
void dfs(int v, int cnt)
{
    used[v] = cnt;
    for (int u : adj[v])
    {
        if (!used[u])
            dfs(u, cnt);
    }
}



int cnt = 0;
int hasEdge(int u, int v)
{
    cnt ++;
    if (n * (n - 1) / 2 - cnt < 1e4 && cnt % 10 ==0)
        random_shuffle();
    //cout << "----------------" << endl;
    if (u > v)
        swap(u, v);
    int hs = u * n + v;
    if (!in_mst[hs])
    {
        in_st[hs] = 0;
        return 0;
    }
    for (int i = 0; i < n; i ++)
        adj[i].clear(), used[i] = 0;
    vector < int > new_st;
    for (int cur: st)
    {
        if (in_st[cur])
            new_st.push_back(cur);
    }
    st = new_st;

    for (int edge : mst)
    {
        if (edge == hs)
            continue;
            ///cout << edge / n << " " << edge % n << endl;
        adj[edge / n].push_back(edge % n);
        adj[edge % n].push_back(edge / n);
    }


    dfs(0, 1);
    for (int i = 0; i < n; i ++)
        if (used[i] == 0)
    {
        dfs(i, 2);
        break;
    }


    for (int edge : st)
    {
        if (edge == hs)
            continue;
        if (used[edge / n] != used[edge % n])
        {
            ///cout << "replace " << edge / n << " " << edge % n << endl;
            in_st[hs] = 0;
            in_mst[edge] = 1;
            mst.push_back(edge);
            in_mst[hs] = 0;
            int pt = 0;
            while(mst[pt] != hs)
                pt ++;
            mst.erase(mst.begin() + pt);
            in_st[edge] = 0;
            /**st.erase(hs);
            mst.insert(edge);
            st.erase(edge);
            mst.erase(hs);*/
            return 0;
        }
    }

    return 1;
}

Compilation message (stderr)

game.cpp: In function 'void random_shuffle()':
game.cpp:16:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |     for (int i = 0; i < st.size(); i ++)
      |                     ~~^~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 27 / 27
• Subtask 3: 0 / 58