제출 #1014547

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1014547		JakobZorz	가장 긴 여행 (IOI23_longesttrip)	C++17	85 / 100	17 ms	1060 KiB

longesttrip

#include"longesttrip.h"
#include<iostream>
#include<algorithm>
#include<map>
using namespace std;

int n;
int perm[1000];
vector<pair<int,int>>unc; // not connected
map<pair<int,int>,bool>cache;

vector<int>per(vector<int>arr){
    for(int&i:arr)
        i=perm[i];
    return arr;
}

bool connected(vector<int>a,vector<int>b){
    return are_connected(per(a),per(b));
}

bool connected(int a,int b){
    if(a>b)
        swap(a,b);
    if(cache.count({a,b}))
        return cache[{a,b}];
    return cache[{a,b}]=connected(vector<int>({a}),vector<int>({b}));
}

pair<int,int>find_conn(vector<int>v1,vector<int>v2){
    int l1=0,r1=(int)v1.size();
    while(l1<r1-1){
        int mid=(l1+r1)/2;
        vector<int>v;
        for(int i=l1;i<mid;i++)
            v.push_back(v1[i]);
        if(connected(v,v2))
            r1=mid;
        else
            l1=mid;
    }
    
    int l2=0,r2=(int)v2.size();
    while(l2<r2-1){
        int mid=(l2+r2)/2;
        vector<int>v;
        for(int i=l2;i<mid;i++)
            v.push_back(v2[i]);
        if(connected({v1[l1]},v))
            r2=mid;
        else
            l2=mid;
    }
    
    return{v1[l1],v2[l2]};
}

vector<int>merge(vector<int>v1,vector<int>v2){
    while(v2.size()){
        v1.push_back(v2.back());
        v2.pop_back();
    }
    return v1;
}

pair<vector<int>,vector<int>>merge(vector<int>v1,vector<int>v2,vector<int>v3){
    if(connected(v1.back(),v2.back()))
        return{merge(v1,v2),v3};
    unc.emplace_back(v1.back(),v2.back());
    if(connected(v2.back(),v3.back()))
        return{merge(v2,v3),v1};
    unc.emplace_back(v2.back(),v3.back());
    
    return{merge(v1,v3),v2};
}

vector<int>cyclic_shift(vector<int>arr,int a){
    // it ends with a
    vector<int>res;
    bool b1=false;
    for(int i:arr){
        if(b1)
            res.push_back(i);
        if(i==a)
            b1=true;
    }
    
    bool b2=true;
    for(int i:arr){
        if(b2)
            res.push_back(i);
        if(i==a)
            b2=false;
    }
    return res;
}

vector<int>longest_trip(int N,int D){
    cache.clear();
    srand(54367582);
    n=N;
    unc.clear();
    for(int i=0;i<n;i++)
        perm[i]=i;
    for(int i=0;i<n;i++)
        swap(perm[i],perm[rand()%n]);
    
    vector<vector<int>>arr;
    for(int i=0;i<n;i++)
        arr.push_back({i});
    
    while(arr.size()>2){
        vector<int>v1,v2,v3;
        v1=arr.back();
        arr.pop_back();
        v2=arr.back();
        arr.pop_back();
        v3=arr.back();
        arr.pop_back();
        auto res=merge(v1,v2,v3);
        arr.push_back(res.first);
        arr.push_back(res.second);
    }
    
    
    vector<int>res1=arr[0];
    vector<int>res2=arr[1];
    
    if(!connected(res1,res2)){
        if(res1.size()>res2.size())
            return per(res1);
        else
            return per(res2);
    }
    
    if(connected(res1.back(),res2.back()))
        return per(merge(res1,res2));
    reverse(res1.begin(),res1.end());
    if(connected(res1.back(),res2.back()))
        return per(merge(res1,res2));
    reverse(res2.begin(),res2.end());
    if(connected(res1.back(),res2.back()))
        return per(merge(res1,res2));
    reverse(res1.begin(),res1.end());
    if(connected(res1.back(),res2.back()))
        return per(merge(res1,res2));
    
    vector<bool>in_res1(n);
    for(int i:res1)
        in_res1[i]=true;
    
    // both must be cyclical then
    pair<int,int>pr={-1,-1};
    
    for(auto[u,v]:unc){
        if(in_res1[u]==in_res1[v]){
            if(in_res1[u]){
                if(connected(res2[0],u)){
                    pr={u,res2[0]};
                }else{
                    pr={v,res2[0]};
                }
            }else{
                if(connected(res1[0],u)){
                    pr={res1[0],u};
                }else{
                    pr={res1[0],v};
                }
            }
            break;
        }
    }
    
    if(pr.first==-1)
        pr=find_conn(res1,res2);
    
    vector<int>r1=cyclic_shift(res1,pr.first);
    vector<int>r2=cyclic_shift(res2,pr.second);
    return per(merge(r1,r2));
}

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