Submission #433964

#	Time	Username	Problem	Language	Result	Execution time	Memory
433964		AugustinasJucas	Highway Tolls (IOI18_highway)	C++14	51 / 100	300 ms	262148 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
const int dydis = 1e5 + 10;
vector<pair<int, int> > gr[dydis];
int n, m;
long long light, heavy;
int tevas[dydis];
int dist[dydis];
int virs[dydis];
vector<pair<int, int> > brn;
int getLen(){
	vector<int> st;
	for(int i = 0; i < m; i++) st.push_back(0);
	return 1ll * ask(st) / light;
}
void dfs(int v, int came = -1, int dst = 0){
	dist[v] = dst;
	if(came == -1) virs[v] = -1;
	for(auto x : gr[v]){
		if(x.first == came) continue;
		tevas[x.first] = v;
		virs[x.first] = x.second;
		dfs(x.first, v, dst+1);
	}
}
vector<pair<int, int> > getInds(int v, int len){ // first - brianos indeksas, sec - virsunes
	dfs(v, -1);
	vector<pair<int, int> > ret;
	for(int i = 0; i < n; i++){
		if(dist[i] != len) continue;
		ret.push_back({virs[i], i});
	}
	return ret;
}
pair<int, int> solveWhenHave(int v, int len){
	vector<pair<int, int> > inds = getInds(v, len); // cia turetu visi buti blogi, isskyrus viena!
	int l = 0; int r = inds.size()-1; int mid = -1; int kair = inds.size()-1;
	vector<int> askk(m, 0);
	long long turi = len * light;
	while(l <= r){
		mid = (l + r) / 2;
		for(int i = 0; i <= mid; i++) askk[inds[i].first] = 1;
		if(ask(askk) != turi){
			r = mid-1;
			kair = min(kair, mid);
		}else{
			l = mid+1;
		}
		for(int i = 0; i <= mid; i++) askk[inds[i].first] = 0;
	}
	return {v, inds[kair].second};
}
/*
int findOne(int len){ //randa viena node'a
	vector<pair<int, int> > inds;
	for(int i = 0; i < (int) brn.size(); i++) inds.push_back({i, brn[i].first});
	int l = 0; int r = inds.size()-1; int mid = -1; int kair = inds.size()-1;
	vector<int> askk(m, 0);
	long long turi = len * light;
	while(l <= r){
		mid = (l + r) / 2;
		for(int i = 0; i <= mid; i++) askk[inds[i].first] = 1;
		if(ask(askk) != turi){
			r = mid-1;
			kair = min(kair, mid);
		}else{
			l = mid+1;
		}
		for(int i = 0; i <= mid; i++) askk[inds[i].first] = 0;
	}
	return inds[kair].second;
}*/

int findAukste(vector<pair<int, int> > briaunos, int len){
	int l = 0; int r = briaunos.size()-1; int mid;
	vector<int> st(m, 0);
	long long turi = 1ll * len * light;
	int desn = r;
	//cout << "briaunos: \n"; for(auto x : briaunos) cout << "briauna " << x.first << ", jos galas " << x.second << endl; cout << endl;
	 
	while(l <= r){
		mid = (l + r) / 2;
		for(int i = 0; i <= mid; i++) st[briaunos[i].first] = 1;
		if(ask(st) != turi){
			r = mid-1;
			desn = min(desn, mid);
		}else{
			l = mid+1;
		}
		for(auto & x : st) x = 0;
	}
	return briaunos[desn].second;
}

vector<pair<int, int> > aukstai[dydis];
int findFarthest(int v, int len){
	
	dfs(v, -1);
	int mx = 0;
	for(int i = 0; i < n; i++){
		aukstai[dist[i]].push_back({virs[i], i});
		mx = max(mx, dist[i]);
	}
	int l = 1, r = mx, mid;
	long long turi = 1ll * len  * heavy;
	vector<int> st(m, 0);
	int ans = 0;
	while(l <= r){
		mid = (l + r) / 2;
		for(int i = 1; i <= mid; i++){
			for(auto x : aukstai[i]) st[x.first] = 1;
		}
		if(ask(st) == turi){
			r = mid-1;
		}else{
			ans = max(ans, mid);
			l = mid+1;
		}
		for(auto &x : st) x = 0;
	}
	// galas yra ans aukste
	ans++;
	//cout << "galas yra " << ans << " aukste nuo " << v << endl;
	return findAukste(aukstai[ans], len);
}
pair<int, int> solveEil(int len){
	long long turi = light * len;
	int leftmost = -1;
	int l = 0; int r = n-1; int mid;
	vector<int> st(m, 0);
 	while(l <= r){
		mid = (l + r) / 2;
		for(int i = 0; i <= mid; i++) st[i] = 1;
		if(ask(st) == turi){
			leftmost = max(leftmost, mid);
			l = mid+1;
		}else{
			r = mid-1;
		}
		for(int i = 0; i <= mid; i++) st[i] = 0;
	}
	//cout << "leftmost = " << leftmost << endl;
	int raitmost = n-1;
	l = 0; r = n-1;
	while(l <= r){
		mid = (l + r) /2;
		for(int i = mid; i <= n-1; i++) st[i] = 1;
		if(ask(st) == turi){
			raitmost = min(raitmost, mid);
			r = mid-1;
		}else{
			l = mid+1;
		}
		for(int i = mid; i <= n-1; i++) st[i] = 0;
	}
	return {leftmost+1, raitmost};
	
}
/*
 6 5
5 7
1 3
0 1    
1 2
2 3
3 4
4 5

*/
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
	n = N;
	m = V.size();
	light = A; heavy = B;
	bool eile = 1;
	for(int i = 0; i < m; i++){
		gr[U[i]].push_back({V[i], i});
		gr[V[i]].push_back({U[i], i});
		brn.push_back({V[i], U[i]});
		if(!(U[i] == i && V[i] == i+1)) eile = 0;
	}
	int len = getLen();
	if(eile){
		auto ret = solveEil(len);
		answer(ret.first, ret.second);
		return ;
	}
	
	int uu = findFarthest(0, len);
	//cout << "galas yra " << uu << endl;
	auto ans = solveWhenHave(uu, len);
	answer(ans.first, ans.second);
	return ;
	
}
/*

12 11 5 7 6 10
0 2
0 3
2 4
2 5
3 6
3 7
4 8
5 9
8 10
8 11
9 1

*/

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31