Submission #264948

#	Time	Username	Problem	Language	Result	Execution time	Memory
264948		Basilhijaz	Highway Tolls (IOI18_highway)	C++11	5 / 100	159 ms	12448 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>

using namespace std;

vector<vector<pair<int, int> > > adj2(100000);
pair<int, int> parents[100000];
bool visited[100000];

void dfs(int s, int parent, int ind){
    if(!visited[s]){
        parents[s] = {parent, ind};
        visited[s] = 1;
        for(int i = 0; i < adj2[s].size(); i++){
            dfs(adj2[s][i].first, s, adj2[s][i].second);
        }
    }
}

void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
  int M = U.size();
  vector<int> w(M);
  for(int i = 0; i < M; i++){
    w[i] = 0;
  }
  vector<vector<pair<int, int> > > adj(N);
  for(int i = 0; i < M; i++){
    adj2[U[i]].push_back({V[i], i});
    adj2[V[i]].push_back({U[i], i});
  }
  dfs(0, 0, 0);
  for(int i = 1; i < N; i++){
    adj[parents[i].first].push_back({i, parents[i].second});
  }
  long long curr = ask(w);
  int where = 0;
  bool ok = 1;
  while(ok){
    ok = 0;
    int lo = 0; int hi = adj[where].size() - 1;
    int best = -1;
    while(lo <= hi){
        int mid = (lo + hi)/2;
        for(int j = lo; j <= mid; j++){
            w[adj[where][j].second] = !w[adj[where][j].second];
        }
        long long last = ask(w);
        if(last != curr){
            hi = mid - 1;
            ok = 1;
            best = adj[where][mid].first;
            curr = last;
        }
        else{
            lo = mid + 1;
        }
    }
    if(ok)where = best;
  }
  answer(0, where);
}

Compilation message (stderr)

highway.cpp: In function 'void dfs(int, int, int)':
highway.cpp:14:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |         for(int i = 0; i < adj2[s].size(); i++){
      |                        ~~^~~~~~~~~~~~~~~~

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