Submission #834671

#	Time	Username	Problem	Language	Result	Execution time	Memory
834671		merlin	Simurgh (IOI17_simurgh)	C++14	51 / 100	2342 ms	2900 KiB

simurgh

#include<bits/stdc++.h>
#include "simurgh.h"
using namespace std;
#define ll long long
#define f first
#define s second

void setIO(string name="") {
	cin.tie(0)->sync_with_stdio(0);
	if (!name.empty()) {
		freopen((name+".in").c_str(), "r", stdin);
		freopen((name+".out").c_str(), "w", stdout);
	}
}

struct dsu{
    vector<int> par;
    int comps;
    dsu(int n){
        par = vector<int>(n,-1);
        comps = n;
    }
    int find(int a){
        if(par[a] < 0) return a;
        par[a] = find(par[a]);
        return par[a];
    }
    void merge(int a,int b){
        a = find(a);
        b = find(b);
        if(a == b) return;
        comps--;
        if(par[a] > par[b]) swap(a,b);
        par[a] += par[b];
        par[b] = a;
    }
};
vector<vector<pair<int,int>>> sus;

bool dfs(int cur,int par,int target,vector<int> &ret){
    if(cur == target) return 1;
    for(auto i : sus[cur])if(i.f != par){
        if(dfs(i.f,cur,target,ret)){
            ret.push_back(i.s);
            return 1;
        }
    }
    return 0;
}

int ask(unordered_set<int> a){
    vector<int> payload;
    for(auto i : a)payload.push_back(i);
    return count_common_roads(payload);
}

vector<int> find_roads(int n,vector<int> u,vector<int> v){
    assert(n <= 240);
    int m = u.size();
    vector<int> active(m,1);
    vector<int> ans;
    while(ans.size() < n-1){
        //for(auto i : ans)cerr<<i<<" ";cerr<<endl;
        dsu uf(n);
        vector<int> teraz = ans;
        sus = vector<vector<pair<int,int>>>(n);
        for(auto i : ans){
            uf.merge(u[i],v[i]);
            sus[u[i]].push_back({v[i],i});
            sus[v[i]].push_back({u[i],i});
        }
        int navyse = -1;
        for(int i = 0;i<m;i++)if(active[i]){
            if(uf.find(u[i]) == uf.find(v[i])){
                if(navyse == -1){
                    navyse = i;
                    teraz.push_back(i);
                    //cerr<<"navyse "<<i<<endl;
                }
            }else{
                sus[u[i]].push_back({v[i],i});
                sus[v[i]].push_back({u[i],i});
                teraz.push_back(i);
                //cerr<<i<<endl;
            }
            uf.merge(u[i],v[i]);
        }
        if(navyse == -1) return teraz;
        vector<int> zaujimave;
        dfs(u[navyse],-1,v[navyse],zaujimave);
        zaujimave.push_back(navyse);
        //for(auto i : zaujimave) cerr<<i<<" ";cerr<<endl;
        unordered_set<int> payload;
        for(auto i : teraz) payload.insert(i);
        vector<int> anss;
        int low = 1<<30;
        for(auto i : zaujimave){
            if(active[i]){
                payload.erase(i);
                int tmp = ask(payload);
                low = min(low,tmp);
                anss.push_back(tmp);
                payload.insert(i);
            }else{
                anss.push_back(-1);
            }
        }
        int low_num = 0;
        for(int i : anss)if(i <= low) low_num++;
        for(int i = 0;i<anss.size();i++){
            if(low_num != anss.size() && anss[i] == low && active[zaujimave[i]]){
                //cerr<<zaujimave[i]<<" dobra"<<endl;
                ans.push_back(zaujimave[i]);
            }
            active[zaujimave[i]] = 0;
        }
    }
    return ans;
}

Compilation message (stderr)

simurgh.cpp: In function 'std::vector<int> find_roads(int, std::vector<int>, std::vector<int>)':
simurgh.cpp:62:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   62 |     while(ans.size() < n-1){
      |           ~~~~~~~~~~~^~~~~
simurgh.cpp:110:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  110 |         for(int i = 0;i<anss.size();i++){
      |                       ~^~~~~~~~~~~~
simurgh.cpp:111:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  111 |             if(low_num != anss.size() && anss[i] == low && active[zaujimave[i]]){
      |                ~~~~~~~~^~~~~~~~~~~~~~
simurgh.cpp: In function 'void setIO(std::string)':
simurgh.cpp:11:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |   freopen((name+".in").c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
simurgh.cpp:12:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |   freopen((name+".out").c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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