Submission #98815

#	Time	Username	Problem	Language	Result	Execution time	Memory
98815		Just_Solve_The_Problem	Highway Tolls (IOI18_highway)	C++11	0 / 100	247 ms	64292 KiB

highway

#include "highway.h"
//#include "grader.cpp"
#include <vector>
#include <map>
#include <utility>
#include <iostream>

#define ll long long

using namespace std;

const int maxn = (int)1e5 + 7;

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

void dfs(int v, int pr) {
	vec[h[v]].push_back(v);
	p[v] = pr;
	for (int to : gr[v]) {
		if (to == pr) continue;
		h[to] = h[v] + 1;
		w[mp[{v, to}]] = 1;
		dfs(to, v);
	}
}

void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
	int m = U.size();
	ll dist = 0;
	w.resize(m, 0);
	dist = ask(w) / A;
	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;
		}
		for (int i = mid + 1; i < m; i++) {
			w[i] = 0;
		}
		ll T = ask(w);
		if (T > dist * A) {
			r = mid;
		} else {
			l = mid;
		}
	}
	int a, b;
	a = U[r];
	b = V[r];
	for (int i = 0; i < m; i++) {
		w[i] = 0;
	}
	dfs(a, b);
	int s, t;
	ll asd = (ask(w) - dist * A) / (B - A);
	l = -1;
	r = vec[asd].size() - 1;
	while (r - l > 1) {
		int mid = (l + r) >> 1, v;
		for (int i = 0; i <= mid; i++) {
			v = vec[asd][i];
			w[mp[{v, p[v]}]] = 1;
		}
		for (int i = mid + 1; i < vec[asd].size(); i++) {
			v = vec[asd][i];
			w[mp[{v, p[v]}]] = 0;
		}
		ll T = ask(w);
		if (T > A) {
			r = mid;
		} else {
			l = mid;
		}
	}
	s = vec[asd][r];
	for (int i = 0; i < maxn; i++) {
		vec[i].clear();
	}
	h[s] = 0;
	dfs(s, s);
	asd = dist;
	l = -1;
	r = vec[asd].size() - 1;
	while (r - l > 1) {
		int mid = (l + r) >> 1, v;
		for (int i = 0; i <= mid; i++) {
			v = vec[asd][i];
			w[mp[{v, p[v]}]] = 1;
		}
		for (int i = mid + 1; i < vec[asd].size(); i++) {
			v = vec[asd][i];
			w[mp[{v, p[v]}]] = 0;
		}
		ll T = ask(w);
		if (T > A) {
			r = mid;
		} else {
			l = mid;
		}
	}
	t = vec[asd][r];
	answer(s, t);
}
/*
7 6 4 5 0 5
0 2
1 2
2 3
3 4
4 5
4 6
*/

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:79:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = mid + 1; i < vec[asd].size(); i++) {
                         ~~^~~~~~~~~~~~~~~~~
highway.cpp:105:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = mid + 1; i < vec[asd].size(); i++) {
                         ~~^~~~~~~~~~~~~~~~~

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