Submission #139475

#	Time	Username	Problem	Language	Result	Execution time	Memory
139475		CaroLinda	Highway Tolls (IOI18_highway)	C++14	12 / 100	210 ms	8948 KiB

highway

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

#define debug printf
#define lp(i,a,b) for(int i=a;i<b;i++)
#define pii pair<int,int>
#define ll long long
#define ff first
#define ss second
#define pb push_back
#define mk make_pair

const int MAXN = 9e4+ 10 ;
const int MAXM = 13e4+10 ;

using namespace std ;

struct Edge
{

	int j , id ;

	Edge(int j = 0 , int id = 0) 
		: j(j) , id(id) {}

} ;

int n , m , S , T ;

vector<int> toAsk , possible ;

ll oldVal , newVal , rad ;

bool marc[MAXN] ;

vector<Edge> adj[MAXN] ;

int edgePai[MAXN] ;

// --------------------------------

void dfs(int x , ll depth )
{

	if( depth == rad ) possible.pb(x) ;

	marc[x] = true ;

	for(Edge e : adj[x])
		if( !marc[e.j] ) 
		{
			edgePai[e.j] = e.id ;
			dfs(e.j,depth+1) ;
		}

}

void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
  
  m = U.size();
  n = N ;

  lp(i,0,m)
  {

  		
  	int a = U[i] , b = V[i] ;

  	adj[a].pb(Edge(b,i)) ;
  	adj[b].pb(Edge(a,i)) ;

  	toAsk.pb(0) ;

  }

  oldVal = ask(toAsk) ;
  rad = oldVal/A ;

  edgePai[0] = -1 ;
  dfs(0,0) ;

  int l = 0 , r = possible.size() - 1 , mid , best = 0 ;

  while(l<=r)
  {
  		mid = (l+r)/2 ;

  		lp( i, l , mid+1 )
  			toAsk[ edgePai[possible[i]] ] = 1 ;

  		newVal = ask(toAsk) ;

  		lp(i,l,mid+1) 
  			toAsk[ edgePai[possible[i]] ] = 0 ;

  		 if( A < B ? newVal > oldVal : newVal < oldVal ) 
  		 {
  		 	r = mid - 1;
  		 	best = mid ;
  		 }

  		 else l = mid+1 ;

  }

  T = possible[best] ;

  answer(S,T) ;
  

}
 

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