Submission #98893

#	Time	Username	Problem	Language	Result	Execution time	Memory
98893		Just_Solve_The_Problem	Highway Tolls (IOI18_highway)	C++11	100 / 100	980 ms	46172 KiB

highway

#include "highway.h"
//#include "grader.cpp"
#include <vector>
#include <map>
#include <utility>
#include <iostream>
#include <queue>
 
#define ll long long
 
using namespace std;
 
const int maxn = (int)2e5 + 7;

vector < int > gr[maxn];
vector < int > nwgr[maxn];
vector < int > vec[maxn];
vector < int > w;
vector < int > del;
map < pair < int, int >, int > mp;
int id[maxn], h[maxn], p[maxn], idc[maxn];

int get(int a) {
	if (id[a] == a) return a;
	return id[a] = get(id[a]);
}

void connect(int a, int b) {
	a = get(a);
	b = get(b);
	id[a] = b;
}

void addedge(int a, int b) {
	nwgr[a].push_back(b);
	nwgr[b].push_back(a);
}
 
void dfs(int v, int pr) {
	vec[h[v]].push_back(v);
	p[v] = pr;
	idc[v] = mp[{v, pr}];
	for (int to : nwgr[v]) {
		if (to == pr) continue;
		h[to] = h[v] + 1;
		del.push_back(mp[{v, to}]);
		w[del.back()] = 1;
		dfs(to, v);
	}
}
 
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
	int n = N, s, t;
	int m = U.size();
	ll dist = 0;
	w.resize(m, 0);
	dist = ask(w) / A;
	for (int i = 0; i < n; i++) {
		id[i] = i;
	}
	for (int i = 0; i < m; i++) {
		int u, v;
		u = U[i];
		v = V[i];
		mp[{v, u}] = mp[{u, v}] = i;
		gr[u].push_back(v);
		gr[v].push_back(u);
	}
	int l = -1;
	int r = m - 1;
	while (r - l > 1) {
		int mid = (l + r) >> 1;
		for (int i = 0; i <= mid; i++) {
			w[i] = 1;
		}
		ll T = ask(w);
		for (int i = 0; i <= mid; i++) {
			w[i] = 0;
		}
		if (T == dist * A) {
			l = mid;
		} else {
			r = mid;
		}
	}
	for (int i = 0; i < m; i++) {
		w[i] = 1;
	}
	int u, v;
	u = U[r];
	v = V[r];
	queue < int > q;
	q.push(u);
	q.push(v);
	addedge(u, v);
	connect(u, v);
	w[r] = 0;
	while (!q.empty()) {
		int asd = q.front();
		q.pop();
		for (int to : gr[asd]) {
			if (get(to) != get(asd)) {
				addedge(asd, to);
				connect(asd, to);
				w[mp[{asd, to}]] = 0;
				q.push(to);
			}
		}
	}
	dfs(u, v);
	vector < int > ord;
	for (int i = 0; i < n; i++) {
		for (int to : vec[i]) {
			ord.push_back(to);
		}
		vec[i].clear();
	}
	l = -1;
	r = ord.size() - 1;
	while (r - l > 1) {
		int mid = (l + r) >> 1;
		for (int i = 0; i <= mid; i++) {
			w[idc[ord[i]]] = 0;
		}
		ll T = ask(w);
		for (int i = 0; i <= mid; i++) {
			w[idc[ord[i]]] = 1;
		}
		if (T == dist * A) {
			r = mid;
 		} else {
			l = mid;
 		}
	}
	s = ord[r];
	ord.clear();
	h[v] = 0;
	for (int to : del) {
		w[to] = 0;
	}
	del.clear();
	dfs(v, u);
	for (int i = 0; i < n; i++) {
		for (int to : vec[i]) {
			ord.push_back(to);
		}
	}
	l = -1;
	r = ord.size();
	while (r - l > 1) {
		int mid = (l + r) >> 1;
		for (int i = 0; i <= mid; i++) {
			w[idc[ord[i]]] = 0;
		}
		ll T = ask(w);
		for (int i = 0; i <= mid; i++) {
			w[idc[ord[i]]] = 1;
		}
		if (T == dist * A) {
			r = mid;
 		} else {
			l = mid;
 		}
	}
	t = ord[r];
	answer(s, t);
}
/*
8 10 1 2 0 2
0 1
0 2
0 3
1 4
0 5
5 6
2 7
2 3
3 6
5 7


*/

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