Submission #169751

#	Time	Username	Problem	Language	Result	Execution time	Memory
169751		CaroLinda	Towns (IOI15_towns)	C++14	25 / 100	21 ms	504 KiB

towns

#include <bits/stdc++.h>
#include "towns.h"
 
#define debug printf
#define lp(i,a,b) for(int i = a ; i < b ; i++ )
#define ff first
#define ss second
#define pb push_back
#define mk make_pair
#define ll long long
#define sz size()
#define pii pair<int,int>
#define all(x) x.begin(),x.end()
#define tiii tuple<int,int,int>
#define mkt make_tuple
 
const int MAXN = 120 , inf = 1e9+10 ;
 
using namespace std ;
 
int n , v , s , t , r ;
int myRadio[MAXN] , pai[MAXN] ;
int d[MAXN][MAXN] ;
stack<int> List, bucket ;
vector<int> comp[MAXN] ;

inline void ask(int i , int j)
{
 
	if( d[i][j] == -1 ) 
		d[i][j] = d[j][i] = getDistance(i,j) ;
 
}

bool isDiff(int i, int j)
{
	if( myRadio[i] < r && myRadio[j] < r ) return false ;
	else if( myRadio[i] > r && myRadio[j] > r ) return false ;
	if( !(myRadio[i] == myRadio[j] && myRadio[i] == r) ) return true ;
 
	ask(i,j) ;
	return d[s][i] + d[s][j] - d[i][j] == 2*r; 
}

void print(stack<int> a , stack<int> b )
{

	debug("Printing stacks\n") ;
	while(!a.empty()) debug("%d " , a.top() ) , a.pop() ;
	debug("\n") ;
	while(!b.empty()) debug("%d " , b.top() ) , b.pop() ;
	debug("\n\n") ;

}

int find(int x) 
{
	if( x == pai[x] ) return x ;
	return pai[x] = find(pai[x]);
}

void join(int a, int b)
{
	a = find(a) ; 
	b=find(b) ;
	if(a == b) return ;
	if( comp[a].sz < comp[b].sz ) swap( a ,b ) ;
	for(int i : comp[b])
		comp[a].pb(i) ;
	comp[b].clear() ;
	pai[b] = a ;
}

int hubDistance(int N, int sub)
{
 
	memset(d, -1, sizeof d ) ;
	lp(i,0,N) d[i][i] =0  ;
 
	n = N ;
 
	lp(i,0,n) ask(0,i) ;
	v = 0 ;
 
	s = max_element( d[v] , d[v]+n ) - d[v] ;
 
	lp(i,0,n) ask(s,i) ;
	t = max_element( d[s] , d[s] + n ) - d[s] ;

 
 	r = inf ;

	
 	lp(i,0,n)
 	{

 		myRadio[i] = ( d[v][s] + d[s][i] - d[v][i] ) >> 1 ; 
 		r = min(r, max( myRadio[i] , d[s][t] - myRadio[i] )  ) ;

 	}

 	int toLeftS=0 , toRightS=0 , toLeftT=0 , toRightT=0 ;
 	vector<int> auxS , auxT , toTest ;

 	lp(i,0,n)
 	{

 		if( myRadio[i] < r ) toLeftS ++ ;
 		else if( myRadio[i] > r ) toRightS ++ ;
 		else toTest.pb(i) ;

 		int aux = d[s][t] - myRadio[i] ;

 		if( aux < r ) toRightT ++ ;
 		else if( aux > r ) toLeftT ++ ;
 		else auxT.pb(i) ;
 	}

 	toLeftS = max(toLeftS, toRightS ) ;
 	toLeftT = max(toLeftT, toRightT ) ;

 	if( sub <= 2 ) return r ;

 	if( toLeftS > n/2 )
 	{
 		if( toLeftT > n/2 ) return -r ;
 		r = d[s][t] - r ;
 		swap(toTest, auxT ) ;
 	}

 	lp(i,0,n)
 	{
 		pai[i] = i ;
 		comp[i].pb(i) ;
 	}

 	lp(i,0,n)
 		lp(j,i+1,n)
 			if( !isDiff(i,j) )
 				join(i,j) ;

 	int mx = -1 ;

 	lp(i,0,n) mx = max( mx, (int)(comp[find(i)].sz) ) ;

 	if( mx > n/2 ) return -r ;
 	return r ;

}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:85:35: warning: conversion to 'int' from 'long int' may alter its value [-Wconversion]
  s = max_element( d[v] , d[v]+n ) - d[v] ;
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
towns.cpp:88:37: warning: conversion to 'int' from 'long int' may alter its value [-Wconversion]
  t = max_element( d[s] , d[s] + n ) - d[s] ;
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 12 / 12
• Subtask 3: 0 / 13
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 39