Submission #139417

#	Time	Username	Problem	Language	Result	Execution time	Memory
139417		wilwxk	Highway Tolls (IOI18_highway)	C++14	0 / 100	532 ms	262148 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
 
const int MAXN=9e4+5;
vector<int> g[MAXN], config;
vector<int> bons;
int aresta[MAXN*2][2];
int pid[MAXN], lvl[MAXN];
bool ruim[MAXN];
int n, m, x, y;
ll tam;
 
void pinta(int ini, int fim, int k) {
  if(fim<ini||ini<0) return;
  for(int i=ini; i<=fim; i++) config[pid[bons[i]]]=k;
}
 
void dfs(int cur, int pp, int d) {
  pid[cur]=pp; lvl[cur]=d;
  for(auto vid : g[cur]) {
    if(vid==pp) continue;
    int viz= aresta[vid][ aresta[vid][0]==cur ];
    dfs(viz, vid, d+1);
  }
}
 
// int divide(int cur) {
//  return 1;
//   for(auto vid : g[cur]) {
    
//  }
// }
 
// int conquer(int cur) {
 
// }
 
void acaba() {
  if(bons.size()==2) {
    answer(bons[0], bons[1]);
    return;
  }
  // for(auto cur : bons) printf("bb %d (%d)\n", cur, pid[cur]); cout << endl;
  
  vector<int> aux;
  int mid=(bons.size()+1)/2;
  pinta(0, mid, 1);
  ll val=ask(config);
  // for(auto cur : config) printf("%d ", cur); printf(">> %d %lld %lld\n", mid, val, tam);
 
  if(val==tam) {
    for(int i=mid+1; i<bons.size(); i++) aux.push_back(bons[i]);
    bons.clear();
    for(auto cur : aux) bons.push_back(cur);
  }
  else if(val==tam+2*(y-x)) {
    for(int i=0; i<=mid; i++) aux.push_back(bons[i]);
    bons.clear();
    for(auto cur : aux) bons.push_back(cur);
  }
  else {
    pinta(0, mid, 0);
    random_shuffle(bons.begin(), bons.end());
  }
  pinta(0, mid, 0);
 
  acaba();
}
 
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
  n=N; m=U.size(); x=A; y=B;
  for(int i=0; i<m; i++) {
    int a=U[i]; int b=V[i];
    aresta[i][0]=a; aresta[i][1]=b;
    g[a].push_back(i);
    g[b].push_back(i);
    config.push_back(0);
  }
 
  dfs(0, -1, 0);
  tam=ask(config);
  for(int i=1; i<n; i++) {
    if(lvl[i]==tam/x) bons.push_back(i);
    else ruim[i]=1;
  }
 
  for(int i=0; i<n; i++) {
    if(ruim[i]) {
      dfs(i, -1, 0);
      break;
    }
  } 
  bons.push_back(0);
  fill(config.begin(), config.end(), 0);
  srand(time(0)+n+m); random_shuffle(bons.begin(), bons.end());
  acaba();
}

Compilation message (stderr)

highway.cpp: In function 'void acaba()':
highway.cpp:54:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=mid+1; i<bons.size(); i++) aux.push_back(bons[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