Submission #1064003

#	Time	Username	Problem	Language	Result	Execution time	Memory
1064003		AmirAli_H1	Longest Trip (IOI23_longesttrip)	C++17	85 / 100	13 ms	676 KiB

longesttrip

// In the name of Allah

#include <bits/stdc++.h>
#include "longesttrip.h"
using namespace std;

typedef			long long				ll;
typedef			pair<int, int>			pii;
typedef			pair<ll, ll>			pll;

#define			F						first
#define			S						second
#define			endl					'\n'
#define			sep						' '
#define			pb						push_back
#define			Mp						make_pair
#define			all(x)					(x).begin(),(x).end()
#define			len(x)					((ll) (x).size())

const int maxn = 600 + 7;

int n, d;
bool mark[maxn];
vector<int> res, resx;
vector<int> ls[maxn], vc;

void merge(int i, int j) {
	for (int x : ls[j]) ls[i].pb(x);
	ls[j].clear(); ls[j].shrink_to_fit();
}

pii get_res(int l, int r) {
	if (r - l <= 1) return Mp(l, l);
	int mid = (l + r) / 2;
	pii f1 = get_res(l, mid), f2 = get_res(mid, r);
	
	vc.clear();
	vc.pb(f1.F); vc.pb(f1.S); vc.pb(f2.F); vc.pb(f2.S);
	sort(all(vc)); vc.resize(unique(all(vc)) - vc.begin());
	while (len(vc) > 2) {
		int j1 = vc.back(); vc.pop_back();
		int j2 = vc.back(); vc.pop_back();
		int j3 = vc.back(); vc.pop_back();
		
		if (are_connected({ls[j1].back()}, {ls[j3][0]})) {
			merge(j1, j3);
			vc.pb(j1); vc.pb(j2);
		}
		else if (are_connected({ls[j2].back()}, {ls[j3][0]})) {
			merge(j2, j3);
			vc.pb(j1); vc.pb(j2);
		}
		else {
			reverse(all(ls[j2]));
			merge(j1, j2);
			vc.pb(j1); vc.pb(j3);
		}
	}
	
	return Mp(vc[0], vc[1]);
}

vector<int> longest_trip(int N, int D) {
	n = N; d = D;
	fill(mark, mark + n, 0);
	res.clear(); resx.clear();
	for (int i = 0; i < n; i++) {
		ls[i].clear(); ls[i].pb(i);
	}
	
	if (d >= 2) {
		if (are_connected({0}, {1})) {
			res.pb(0); mark[0] = 1;
			res.pb(1); mark[1] = 1;
		}
		else {
			res.pb(0); mark[0] = 1;
			res.pb(2); mark[2] = 1;
		}
		for (int i = 0; i < n; i++) {
			if (mark[i]) continue;
			if (are_connected({i}, {res.back()})) res.pb(i);
			else {
				resx.clear(); swap(res, resx);
				res.pb(i);
				for (int x : resx) res.pb(x);
			}
			mark[i] = 1;
		}
	}
	else {
		pii f = get_res(0, n);
		int j1 = f.F, j2 = f.S;
		if (!are_connected(ls[j1], ls[j2])) {
			if (len(ls[j1]) >= len(ls[j2])) res = ls[j1];
			else res = ls[j2];
		}
		else {
			if (are_connected({ls[j1].back()}, {ls[j2][0]})) {
				merge(j1, j2);
				res = ls[j1];
			}
			else if (are_connected({ls[j1].back()}, {ls[j2].back()})) {
				reverse(all(ls[j2]));
				merge(j1, j2);
				res = ls[j1];
			}
			else if (are_connected({ls[j1][0]}, {ls[j2][0]})) {
				reverse(all(ls[j1]));
				merge(j1, j2);
				res = ls[j1];
			}
			else if (are_connected({ls[j1][0]}, {ls[j2].back()})) {
				reverse(all(ls[j1])); reverse(all(ls[j2]));
				merge(j1, j2);
				res = ls[j1];
			}
			else {
				int lx = 0, rx = len(ls[j1]);
				while (rx - lx > 1) {
					int mid = (lx + rx) / 2;
					vc.clear();
					for (int i = lx; i < mid; i++) vc.pb(ls[j1][i]);
					if (are_connected(vc, ls[j2])) rx = mid;
					else lx = mid;
				}
				int i1 = lx, v1 = ls[j1][i1];
				
				lx = 0, rx = len(ls[j2]);
				while (rx - lx > 1) {
					int mid = (lx + rx) / 2;
					vc.clear();
					for (int i = lx; i < mid; i++) vc.pb(ls[j2][i]);
					if (are_connected({v1}, vc)) rx = mid;
					else lx = mid;
				}
				int i2 = lx, v2 = ls[j2][i2];
				
				for (int i = (i1 + 1); i < (i1 + 1 + len(ls[j1])); i++) {
					res.pb(ls[j1][i % len(ls[j1])]);
				}
				for (int i = i2; i < (i2 + len(ls[j2])); i++) {
					res.pb(ls[j2][i % len(ls[j2])]);
				}
			}
		}
	}
	return res;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:137:18: warning: unused variable 'v2' [-Wunused-variable]
  137 |     int i2 = lx, v2 = ls[j2][i2];
      |                  ^~

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