Submission #298632

#	Time	Username	Problem	Language	Result	Execution time	Memory
298632		DanerZein	Highway Tolls (IOI18_highway)	C++14	5 / 100	111 ms	13616 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
#define MAX 1000000000000000000
using namespace std;
typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<ii> vi;
vector<vi> G;
vector<int> hl;
ll conc[110];
int isq[110];
ll m,a,b,n;
ll dis[110];
void dijkstra(int x){
  memset(isq,0,sizeof isq);
  for(int i=0;i<n;i++) dis[i]=MAX;
  dis[x]=0;
  priority_queue<ii,vector<ii>,greater<ii>>pq;
  pq.push(ii(0,x));
  while(!pq.empty()){
    int u=pq.top().second;
    isq[u]=0;
    pq.pop();
    for(auto &v:G[u]){
      ll cos;
      if(hl[v.second]==1) cos=b;
      else cos=a;
      if(dis[v.first]>dis[u]+cos){
	dis[v.first]=dis[u]+cos;
	if(!isq[v.first]){
	  pq.push(ii(dis[v.first],v.first));
	  isq[v.first]=1;
	}
      }
    }
  }
}
vector<int> path;
int vis[90010];
void dfs(int u){
  path.push_back(u);
  vis[u]=1;
  for(auto &v:G[u]){
    if(!vis[v.first]) dfs(v.first);
  }
}
void line_graph(int u){
  memset(vis,0,sizeof vis);
  dfs(u);
  hl.assign(m,0);
  int w=ask(hl);
  int no=w/a;
  int l=-1,r=m;
  while(r-l>1){
    int mid=(l+r)/2;
    for(int i=0;i<mid;i++) hl[i]=1;
    for(int i=mid;i<m;i++) hl[i]=0;
    if(ask(hl)!=w) r=mid;
    else l=mid;
  }
  /* for(int i=0;i<path.size();i++){
    cout<<path[i]<<" ";
  }
  cout<<endl;
  cout<<l<<endl;
  cout<<w<<endl<<no<<endl;*/
  int x=path[l];
  int y=path[l+no];
  answer(x,y);
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
  n=N;
  a=A;
  b=B;
  G.resize(N+1);
  for(int i=0;i<U.size();i++){
    int u=U[i],v=V[i];
    G[u].push_back(ii(v,i));
    G[v].push_back(ii(u,i));
  }
  bool sw=0;
  int id=-1;
  for(int i=0;i<N;i++){
    if(G[i].size()>2) sw=1;
    if(G[i].size()==1 and id==-1) id=i;
  }
  m=U.size();
  if(sw==1){
    memset(conc,0,sizeof conc);
    hl.assign(m,0);
    for(int i=0;i<m;i++){
      hl[i]=1;
      dijkstra(0);
      ll co=ask(hl);
      for(int j=0;j<N;j++){
	if(dis[j]==co){
	  conc[j]++;
	}
      }
      hl[i]=0;
    }
    ll t,ma=-1;
    for(int i=0;i<N;i++){
      if(conc[i]>ma){
	ma=conc[i];
	t=i;
      }
    }
    answer(0,t);
  }
  else{
    line_graph(id);
  }
}

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:76:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |   for(int i=0;i<U.size();i++){
      |               ~^~~~~~~~~
highway.cpp:109:11: warning: 't' may be used uninitialized in this function [-Wmaybe-uninitialized]
  109 |     answer(0,t);
      |     ~~~~~~^~~~~

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