Submission #130552

#	Time	Username	Problem	Language	Result	Execution time	Memory
130552		groeneprof	통행료 (IOI18_highway)	C++14	51 / 100	408 ms	262144 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
#define int long long
using namespace std;

struct edge{
	int id, v;
};

int N, M, A, B;
vector<vector<edge> > graph;

void dfs(int u, int par, int id, int d, int dist, vector<int>& idlist, vector<int>& vlist){
	if(d == dist){
		idlist.push_back(id);
		vlist.push_back(u);
	}
	for(edge e : graph[u]) if(e.v!=par){
		dfs(e.v, u, e.id, d+1, dist, idlist, vlist);
	}
}

int findT(int S, int par, int dist, int id, int dist2){
	vector<int> idlist, vlist;
	dfs(S, par, id, 0, dist, idlist, vlist);
	int L = 0, R = idlist.size();
	//for(int i : vlist) //cout<<i<<" ";
	//cout<<endl;
	//for(int i : idlist) //cout<<i<<" ";
	//cout<<endl;
	while(L!=R-1){
		//cout<<"L: "<< L<< " R: "<<R<<endl;
		int Mi = (L+R)/2;
		vector<signed> w(M, 0);
		for(int i = L; i<Mi; i++){
			w[idlist[i]]=1;
		}
		//cout<<ask(w)<<endl;
		if(ask(w)==dist2*A){
			L = Mi;
		}
		else{
			R = Mi;
		}
	}
	return vlist[L];
}

int findedge(int dist){
	int L = 0, R = M;
	while(L!=R-1){
		int Mi = (L+R)/2;
		vector<signed> w(M, 0);
		for(int i = L; i<Mi; i++){
			w[i]=1;
		}
		if(ask(w)==dist*A){
			L = Mi;
		}
		else{
			R = Mi;
		}
	}
	return L;
}

void dfs2(int u, int par, int id, vector<signed> & w){
	w[id] = 1;
	for(edge e : graph[u]) if(e.v!=par){
		dfs2(e.v, u, e.id, w);
	}
}

void find_pair(signed _N, vector<signed> U, vector<signed> V, signed _A, signed _B) {
	N = _N;
	M = U.size();
	A = _A;
	B = _B;
	graph.resize(N);
	for(int i = 0; i<M; i++){
		graph[U[i]].push_back({i, V[i]});
		graph[V[i]].push_back({i, U[i]});
	}
	vector<signed> w(M, 0);
	int dist = ask(w)/A;
	int ed = findedge(dist);
	//cout<<"edge: "<<U[ed]<<" "<<V[ed]<<endl;
	dfs2(V[ed], U[ed], ed, w);
	int d1 = (ask(w)-dist*A)/(B-A)-1;
	int d2 = dist - d1 - 1;
	//cout<<"d1: "<<d1<<" d2: "<<d2<<endl;
	int S = findT(V[ed], U[ed], d1, ed, dist);
	int T = findT(U[ed], V[ed], d2, ed, dist);
	answer(S,T);
}

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