Submission #1100502

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100502		MMihalev	Simurgh (IOI17_simurgh)	C++14	51 / 100	95 ms	4280 KiB

simurgh

#include<iostream>
#include<algorithm>
#include<set>
#include<queue>
#include "simurgh.h"
using namespace std;
const int MAX_N=5e2+3;
const int MAX_M=125000;
int n,m;
int q;
vector<int>edges;
vector<pair<int,int>>g[MAX_N];
bool used[MAX_N];
vector<int>comp;
vector<vector<int>>comps;
int adj[MAX_N];
int numedge[MAX_N][MAX_N];

bool stat[MAX_M];
bool checked[MAX_M];
int forsure;

void reset()
{
    comps.clear();
    edges.clear();
    for(int i=0;i<n;i++)
    {
        adj[i]=-1;
        used[i]=0;
    }
}
void dfs(int u)
{
    if(adj[u]!=-1)
    {
        if(!checked[adj[u]])
        {
            comp.push_back(adj[u]);
        }
        if(stat[adj[u]])forsure=adj[u];
    }
    used[u]=1;
    for(auto [v,edge]:g[u])
    {
        if(used[v])continue;
        edges.push_back(edge);
        dfs(v);
    }
}
void rep(int prev,int edge)
{
    for(int i=0;i<edges.size();i++)
    {
        if(edges[i]==prev){edges[i]=edge;return;}
    }
}
vector<pair<int,int>>s;
int rec(int l,int r)
{
    if(l==r)
    {
        return s[l].first;
    }

    int mid=(l+r)/2;

    int bonus=0;
    edges.clear();
    for(int i=0;i<n;i++)used[i]=0;

    for(int i=l;i<=mid;i++)
    {
        edges.push_back(s[i].first);
        used[s[i].second]=1;
    }

    for(int i=1;i<n;i++)
    {
        if(!used[i]){bonus+=stat[numedge[0][i]];edges.push_back(numedge[0][i]);}
    }

    int cnt=count_common_roads(edges)-bonus;

    if(cnt>0)return rec(l,mid);
    return rec(mid+1,r);
}
vector<int> find_roads(int N, vector<int> u, vector<int> v)
{
    n=N;
    m=u.size();

    vector<int>ans;
    for(int i=0;i<m;i++)
    {
        g[u[i]].push_back({v[i],i});
        g[v[i]].push_back({u[i],i});
        numedge[u[i]][v[i]]=i;
        numedge[v[i]][u[i]]=i;
    }

    if(n<=240)
    {
        for(int u=0;u<n;u++)
        {
            reset();
            used[u]=1;
            for(auto [v,edge]:g[u])
            {
                adj[v]=edge;
            }
            for(auto [v,edge]:g[u])
            {
                if(!used[v])
                {
                    forsure=-1;
                    comp.clear();
                    dfs(v);
                    if(forsure!=-1)
                    {
                        comp.push_back(forsure);
                    }
                    comps.push_back(comp);
                }
            }

            for(auto c:comps)
            {
                edges.push_back(c[0]);
            }

            for(auto c:comps)
            {
                int ma=count_common_roads(edges);q++;
                vector<int>marked;
                marked.push_back(c[0]);
                int prev=c[0];
                int sega=0;

                for(int edge:c)
                {
                    if(edge==c[0])continue;

                    rep(prev,edge);

                    int cur=count_common_roads(edges);q++;
                    if(cur>ma)
                    {
                        sega++;
                        marked.clear();
                        ma=cur;
                        marked.push_back(edge);
                        if(sega==2)break;
                    }
                    else if(cur==ma)
                    {
                        marked.push_back(edge);
                    }

                    prev=edge;
                }

                for(int edge:marked)stat[edge]=1;
            }

            for(auto [v,edge]:g[u])checked[edge]=1;
        }

    }
    else
    {
        for(int u=0;u<n;u++)
        {
            if(u==0)
            {
                vector<int>marked;
                edges.clear();
                for(int v=2;v<n;v++)
                {
                    edges.push_back(numedge[v-1][v]);
                }

                int ma=-1;

                for(auto [v,edge]:g[u])
                {
                    edges.push_back(edge);
                    int cur=count_common_roads(edges);

                    if(cur>ma)
                    {
                        marked.clear();
                        marked.push_back(edge);
                        ma=cur;
                    }
                    else if(cur==ma)marked.push_back(edge);
                }

                for(int edge:marked)stat[edge]=1;

                continue;
            }


            while(1)
            {
                int bonus=0;
                edges.clear();
                s.clear();
                for(int i=0;i<n;i++)used[i]=0;

                for(auto [v,edge]:g[u])
                {
                    if(stat[edge] or v==0)continue;
                    edges.push_back(edge);
                    s.push_back({edge,v});
                    used[v]=1;
                }

                for(int i=1;i<n;i++)
                {
                    if(!used[i]){bonus+=stat[numedge[0][i]];edges.push_back(numedge[0][i]);}
                }

                int cur=count_common_roads(edges)-bonus;

                if(cur==0)break;

                int edge=rec(0,s.size()-1);
                stat[edge]=1;
            }
        }
    }

    for(int i=0;i<m;i++)
    {
        if(stat[i])ans.push_back(i);
    }

    if(ans.size()!=n-1)while(1);

    return ans;
}

Compilation message (stderr)

simurgh.cpp: In function 'void dfs(int)':
simurgh.cpp:44:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   44 |     for(auto [v,edge]:g[u])
      |              ^
simurgh.cpp: In function 'void rep(int, int)':
simurgh.cpp:53:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |     for(int i=0;i<edges.size();i++)
      |                 ~^~~~~~~~~~~~~
simurgh.cpp: In function 'std::vector<int> find_roads(int, std::vector<int>, std::vector<int>)':
simurgh.cpp:108:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  108 |             for(auto [v,edge]:g[u])
      |                      ^
simurgh.cpp:112:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  112 |             for(auto [v,edge]:g[u])
      |                      ^
simurgh.cpp:166:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  166 |             for(auto [v,edge]:g[u])checked[edge]=1;
      |                      ^
simurgh.cpp:185:26: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  185 |                 for(auto [v,edge]:g[u])
      |                          ^
simurgh.cpp:212:26: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  212 |                 for(auto [v,edge]:g[u])
      |                          ^
simurgh.cpp:240:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  240 |     if(ans.size()!=n-1)while(1);
      |        ~~~~~~~~~~^~~~~

• Subtask 1: 13 / 13
• Subtask 2: 17 / 17
• Subtask 3: 21 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30