Submission #130551

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
130551	2019-07-15T13:57:04 Z	groeneprof	Highway Tolls (IOI18_highway)	C++14	6 / 100	411 ms	262148 KB

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){
	vector<int> idlist, vlist;
	dfs(S, par, id, 0, dist, idlist, vlist);
	int L = 0, R = idlist.size();
	while(L!=R-1){
		//cout<<"L: "<< L<< "R: "<<R;
		int Mi = (L+R)/2;
		vector<signed> w(M, 0);
		for(int i = L; i<Mi; i++){
			w[idlist[i]]=1;
		}
		if(ask(w)==dist*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);
	int T = findT(U[ed], V[ed], d2, ed);
	answer(S,T);
}

Subtask #1
0 / 5.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	2 ms	248 KB	Output is correct
2	Incorrect	2 ms	324 KB	Output is incorrect: {s, t} is wrong.
3	Halted	0 ms	0 KB	-

Subtask #2
0 / 7.0

#	Verdict	Execution time	Memory	Grader output
1	Incorrect	3 ms	496 KB	Output is incorrect: {s, t} is wrong.
2	Halted	0 ms	0 KB	-

Subtask #3
6.0 / 6.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	20 ms	2140 KB	Output is correct
2	Correct	36 ms	3884 KB	Output is correct
3	Correct	43 ms	6012 KB	Output is correct
4	Correct	169 ms	14864 KB	Output is correct
5	Correct	164 ms	14904 KB	Output is correct
6	Correct	161 ms	16592 KB	Output is correct
7	Correct	153 ms	18096 KB	Output is correct
8	Correct	162 ms	15820 KB	Output is correct
9	Correct	161 ms	16020 KB	Output is correct