제출 #846639

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
846639		ttamx	가장 긴 여행 (IOI23_longesttrip)	C++17	85 / 100	14 ms	856 KiB

longesttrip

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

using namespace std;

vector<int> perm;

bool ask(vector<int> a,vector<int> b){
    for(auto &x:a)x=perm[x];
    for(auto &x:b)x=perm[x];
    return are_connected(a,b);
}

int bsearch(vector<int> vec,vector<int> fixed){
    int l=0,r=vec.size()-1;
    while(l<r){
        int m=(l+r)/2;
        vector<int> res;
        for(int i=l;i<=m;i++)res.emplace_back(vec[i]);
        if(ask(res,fixed))r=m;
        else l=m+1;
    }
    return l;
}

vector<int> longest_trip(int N, int D){
    perm.resize(N);
    iota(perm.begin(),perm.end(),0);
    if(D==3)return perm;
    if(D==2){
        deque<int> path;
        for(int i=0;i<3;i++)path.emplace_back(i);
        for(int i=1;i<3;i++){
            if(!ask({i-1},{i})){
                swap(path[0],path[i-1]);
                swap(path[2],path[i]);
                break;
            }
        }
        for(int i=3;i<N;i++){
            if(ask({i},{path[0]})){
                path.emplace_front(i);
            }else{
                path.emplace_back(i);
            }
        }
        vector<int> ans;
        for(auto x:path)ans.emplace_back(x);
        return ans;
    }
    shuffle(perm.begin(),perm.end(),mt19937_64());
    vector<int> path[2];
    for(int i=0;i<2;i++)path[i].emplace_back(i);
    for(int i=2;i<N;i++){
        if(ask({i},{path[0].back()})){
            path[0].emplace_back(i);
            continue;
        }
        if(ask({i},{path[1].back()})){
            path[1].emplace_back(i);
            continue;
        }
        while(!path[1].empty()){
            path[0].emplace_back(path[1].back());
            path[1].pop_back();
        }
        path[1].emplace_back(i);
    }
    if(path[0].size()<path[1].size())swap(path[0],path[1]);
    vector<int> ans;
    if(!ask(path[0],path[1])){
        ans=path[0];
    }else if(ask({path[0][0]},{path[1][0]})){
        reverse(path[1].begin(),path[1].end());
        ans=path[1];
        for(auto x:path[0])ans.emplace_back(x);
    }else if(ask({path[0][0]},{path[1].back()})){
        ans=path[1];
        for(auto x:path[0])ans.emplace_back(x);
    }else if(ask({path[0].back()},{path[1][0]})){
        ans=path[0];
        for(auto x:path[1])ans.emplace_back(x);
    }else if(ask({path[0].back()},{path[1].back()})){
        ans=path[0];
        reverse(path[1].begin(),path[1].end());
        for(auto x:path[1])ans.emplace_back(x);
    }else{
        int id0=bsearch(path[0],path[1]);
        int id1=bsearch(path[1],{path[0][id0]});
        for(int i=0;i<path[0].size();i++)ans.emplace_back(path[0][(id0+i+1)%path[0].size()]);
        for(int i=0;i<path[1].size();i++)ans.emplace_back(path[1][(id1+i)%path[1].size()]);
    }
    for(auto &x:ans)x=perm[x];
    return ans;
}

컴파일 시 표준 에러 (stderr) 메시지

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:90:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   90 |         for(int i=0;i<path[0].size();i++)ans.emplace_back(path[0][(id0+i+1)%path[0].size()]);
      |                     ~^~~~~~~~~~~~~~~
longesttrip.cpp:91:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |         for(int i=0;i<path[1].size();i++)ans.emplace_back(path[1][(id1+i)%path[1].size()]);
      |                     ~^~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 45 / 60