Submission #1069040

#	Time	Username	Problem	Language	Result	Execution time	Memory
1069040		Malix	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	14 ms	600 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> tii;
typedef vector<ll> li;
typedef vector<li> lii;
 
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define LSOne(s) ((s)&(-s))
 
ll INF=1e18+10;
int inf=1e9+10;
ll M=1e9+7;

int solve(int bk,int p,int n){
    vi a,b,x;
    x.PB(bk);
    REP(i,p,n){
        a.clear();
        a.PB(x.back());
        b.clear();
        b.PB(i);
        if(are_connected(a,b))x.PB(i);
        else return i;
    }
    return n;
}

pi BS(int l,int r,int x,int y,vi &arr,vi &brr){
    if(l==r&&x==y)return {l,x};
    int m=(l+r)/2;
    int z=(x+y)/2;
    vi a,b;
    REP(i,l,m+1)a.PB(arr[i]);
    REP(i,x,y+1)b.PB(brr[i]);
    if(are_connected(a,b))r=m;
    else l=m+1;
    a.clear();b.clear();
    REP(i,l,r+1)a.PB(arr[i]);
    REP(i,x,z+1)b.PB(brr[i]);
    if(are_connected(a,b))y=z;
    else x=z+1;
    return BS(l,r,x,y,arr,brr);
}

std::vector<int> longest_trip(int n, int d)
{
    if(d==3){
        vi ans;
        REP(i,0,n)ans.PB(i);
        return ans;
    }
    if(d==2){
        deque<int> dq;
        vi a,b;
        a.PB(0);b.PB(1);
        if(are_connected(a,b)){
            dq.PB(0);
            dq.PB(1);
            b.pop_back();b.PB(2);
            if(are_connected(a,b))dq.push_front(2);
            else dq.push_back(2);
        }
        else{
            dq.PB(0);
            dq.PB(2);
            dq.PB(1);
        }
        REP(i,3,n){
            a.clear();b.clear();
            a.PB(dq.back());b.PB(i);
            if(are_connected(a,b))dq.push_back(i);
            else dq.push_front(i);
        }
        vi ans;
        REP(i,0,n){
            ans.PB(dq.front());
            dq.pop_front();
        }
        return ans;
    }
    vi a,b,x,y;
    x.PB(0);
    int tm=solve(0,1,n);
    REP(i,1,tm)x.PB(i);
    if(tm!=n)y.PB(tm);
    if(y.empty())return x;
    int pos=tm+1;
    while(pos<n-1){
        a.clear();b.clear();
        a.PB(x.back());b.PB(pos);
        if(are_connected(a,b)){
            a.clear();b.clear();
            a.PB(y.back());b.PB(pos+1);
            if(are_connected(a,b)){
                x.PB(pos);
                y.PB(pos+1);
                a.clear();b.clear();
                a.PB(pos);b.PB(pos+1);
                if(are_connected(a,b)){
                    reverse(y.begin(),y.end());
                    for(auto u:y)x.PB(u);
                    y.clear();
                    int tmp=solve(x.back(),pos+2,n);
                    REP(i,pos+2,tmp)x.PB(i);
                    if(tmp==n)return x;
                    y.PB(tmp);
                    pos=tmp+1;
                }
                else pos+=2;
            }
            else{
                a.clear();b.clear();
                a.PB(pos);b.PB(pos+1);
                if(are_connected(a,b)){
                    x.PB(pos);
                    x.PB(pos+1);
                    pos+=2;
                }
                else{
                    x.PB(pos+1);
                    y.PB(pos);
                    pos+=2;
                } 
            }
        }
        else{
            y.PB(pos);pos++;
        } 
    }
    if(pos<n){
        a.clear();b.clear();
        a.PB(pos);b.PB(x.back());
        if(are_connected(a,b))x.PB(pos);
        else y.PB(pos);
    }
    if((int)x.size()==n)return x;
    if(!are_connected(x,y)){
        if(x.size()>=y.size())return x;
        else return y;
    }
    a.clear();b.clear();
    a.PB(x.front());b.PB(y.front());
    if(x.size()!=1)a.PB(x.back());
    if(y.size()!=1)b.PB(y.back());
if(are_connected(a,b)){
    a.clear();b.clear();
    a.PB(x.front());b.PB(y.front());
    if(are_connected(a,b)){
        reverse(x.begin(),x.end());
        for(auto u:y)x.PB(u);
        return x;
    }
    a.clear();b.clear();
    a.PB(x.front());b.PB(y.back());
    if(are_connected(a,b)){
        reverse(x.begin(),x.end());
        reverse(y.begin(),y.end());
        for(auto u:y)x.PB(u);
        return x;
    }
    a.clear();b.clear();
    a.PB(x.back());b.PB(y.front());
    if(are_connected(a,b)){
        for(auto u:y)x.PB(u);
        return x;
    }
    a.clear();b.clear();
    a.PB(x.back());b.PB(y.back());
    if(are_connected(a,b)){
        reverse(y.begin(),y.end());
        for(auto u:y)x.PB(u);
        return x;
    }
}
    int s1=x.size(),s2=y.size();
    pi arr=BS(0,s1-1,0,s2-1,x,y);
    vi ans;
    REP(k,arr.F+1,s1)ans.PB(x[k]);
    REP(k,0,arr.F+1)ans.PB(x[k]);
    REP(k,arr.S,s2)ans.PB(y[k]);
    REP(k,0,arr.S)ans.PB(y[k]);
    return ans;
}

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