Submission #1222703

#	Time	Username	Problem	Language	Result	Execution time	Memory
1222703		ByeWorld	Longest Trip (IOI23_longesttrip)	C++20	100 / 100	5 ms	428 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define lf ((id<<1))
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define pb push_back
#define are are_connected
using namespace std;
const int MAXN = 2e5+10;
typedef pair<ll,ll> pii;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int n, d;
vector<int> ans, ans2;

std::vector<int> longest_trip(int N, int D)
{
	n = N; d = D;
	vector<int> arr;
	for(int i=0; i<n; i++) arr.pb(i);
	shuffle(arr.begin(), arr.end(), rng);

	ans.clear(); ans.pb(arr[0]);
	ans2.clear(); ans2.pb(arr[1]);

	bool dis = 0;
	for(int i=2; i<n; i++){
		if(dis){
			dis = 0;
			if(are({arr[i]}, {ans.back()})) ans.pb(arr[i]);
			else ans2.pb(arr[i]);
		} else {
			if(are({arr[i]}, {ans.back()})) dis = 0, ans.pb(arr[i]);
			else if(are({arr[i]}, {ans2.back()})) dis = 1, ans2.pb(arr[i]);
			else {
				dis = 0;
				reverse(ans2.begin(), ans2.end());
				for(auto in : ans2) ans.pb(in);

				ans2.clear(); ans2.pb(arr[i]);
			}
		}
	}

	// for(auto in : ans) cout << in << ' ';
	// 	cout << " in\n";
	// for(auto in : ans2) cout << in << ' ';
	// 	cout << " in2\n";

	if( are(ans, ans2) ){ // 1 conn comp
		vector<int> ret;

		bool cob = 0;
		if(ans2[0] != ans2.back()) cob = are({ans[0]}, {ans2[0], ans2.back()});
		else cob = are({ans[0]}, {ans2[0]} );

		if( cob ){

			if(are({ans[0]}, {ans2.back()})){
				reverse(ans.begin(), ans.end());
				reverse(ans2.begin(), ans2.end());
				for(auto in : ans) ret.pb(in);
				for(auto in : ans2) ret.pb(in);
				ans = ret;
			} else {
				reverse(ans.begin(), ans.end());
				for(auto in : ans) ret.pb(in);
				for(auto in : ans2) ret.pb(in);
				ans = ret;
			}

		} else {

			if(ans2[0] != ans2.back()) cob = are({ans.back()}, {ans2[0], ans2.back()});
			else cob = are({ans.back()}, {ans2[0]} );

			if( cob ){

				if(are({ans.back()}, {ans2.back()})){
					reverse(ans2.begin(), ans2.end());
					for(auto in : ans) ret.pb(in);
					for(auto in : ans2) ret.pb(in);
					ans = ret;
				} else {
					for(auto in : ans) ret.pb(in);
					for(auto in : ans2) ret.pb(in);
					ans = ret;
				}

			} else {
				// tengah di connect
				int up = -1, dw = -1;
				int l=0, r=ans.size()-1, mid=0;

				vector<int> BAW;
				for(int i=0; i<ans2.size(); i++) BAW.pb(ans2[i]);

				while(l<=r){
					mid = md;
					vector<int> all;
					for(int j=0; j<=mid; j++) all.pb(ans[j]);

					if(are(all, BAW)) up = mid, r = mid-1;
					else l = mid+1;
				}
				l = 0, r = ans2.size()-1;
				while(l<=r){
					mid = md;
					vector<int> all;
					for(int j=0; j<=mid; j++) all.pb(ans2[j]);

					if(are(all, {ans[up]})) dw = mid, r = mid-1;
					else l = mid+1;
				}

				for(int j=dw-1; j>=0; j--) ret.pb(ans2[j]);
				for(int j=ans2.size()-1; j>=dw; j--) ret.pb(ans2[j]);

				for(int j=up; j<ans.size(); j++) ret.pb(ans[j]);
				for(int j=0; j<up; j++) ret.pb(ans[j]);
				ans = ret;
			}

		}
	}

	if(ans2.size() > ans.size()) swap(ans2, ans);

	// for(int i=0; i+1<ans.size(); i++)
	// 	if(!are({ans[i]}, {ans[i+1]})) cout <<ans[i] << ' ' << ans[i+1] << " jnck\n";
	return ans;
}

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