Submission #382276

#	Time	Username	Problem	Language	Result	Execution time	Memory
382276		sad	Highway Tolls (IOI18_highway)	C++14	12 / 100	167 ms	8244 KiB

highway

#include<bits/stdc++.h>
#include "highway.h"
#define pb push_back
#define fi first
#define se second
using namespace std;
long long a,b,n;const int N=90090;
int pa[N];long long l;vector<int>vv;vector<pair<int,int>>v[N];
vector<int>w;
void dfs(int x,int p,long long le)
{
    pa[x]=p;
    if(le==0){
        vv.pb(x);return;
    }
    for(auto it:v[x])
    {
        if(it.se==p)continue;
        dfs(it.fi,it.se,le-1);
    }
}
int ch(int ll,int r)
{
    w.clear();
    for(int i=0;i<n-1;i++)w.pb(0);
    for(int i=ll;i<=r;i++)
    {
        w[pa[vv[i]]]=1;
    }
    long long x=ask(w);
    w.clear();
    long long y=a*l;
    if(x>y)return 1;
    return 0;
}
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
  a=A;b=B;
  w.clear();
  n=N;
  for(int i=0;i<n-1;i++)w.pb(0);
  l=ask(w)/a;
  for(int i=0;i<n-1;i++)
  {
      v[V[i]].pb({U[i],i});
      v[U[i]].pb({V[i],i});
  }
  dfs(0,-1,l);
  int  m=vv.size();
  int st=0,end=m-1;
  while(st<end)
  {
      int mid=st+end;mid/=2;
      if(ch(st,mid)) end=mid;
      else st=mid+1;
  }
  answer(0,vv[st]);
}
/*
4 3
1 2
0 3
0 1
1 2
1 3
*/

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