제출 #309833

#제출 시각아이디문제언어결과실행 시간메모리
309833CaroLinda고대 책들 (IOI17_books)C++14
50 / 100
445 ms24056 KiB
#include "books.h"
#include <bits/stdc++.h>
 
#define debug printf
#define lp(i,a,b) for(int i = a ; i < b; i++)
#define pb push_back
#define ff first
#define ss second
#define mk make_pair
#define pii pair<int,int>
#define ll long long 
#define all(x) x.begin(),x.end()
#define sz(x) (int)(x.size())
 
const int MAX = 1e6+10 ;
 
using namespace std ;
 
//Tentando uma ideia (provavelmente vai dar errado mas vamos nessa)
 
int bit[MAX] ;
void upd(int pos, int val)
{
	if(pos == 0 ) return ;
 
	for(int i = pos ; i < MAX ; i += (i&-i) )
		bit[i] = max(bit[i] , val) ;
}
int qry(int pos)
{
	if(pos == 0) return -1 ;
 
	int tot = -1 ;
	for(int i = pos ; i > 0 ; i -= (i&-i) )
		tot = max(tot, bit[i]);
	return tot ;
}
 
 
long long minimum_walk(vector<int> p, int s) 
{
 
	int n = sz(p) ;
	ll ans = 0LL ;
 
	lp(i,0,n) ans += (ll)(abs(p[i]-i)) ;
 
	int L = 0  ;
	int R = n-1 ;
 
	while(L < s && p[L] == L ) L++ ;
	while(R > s && p[R] == R) R-- ;
 
	vector<bool> vis( n, false ) ;
	vector<pii> intervalo(n, make_pair(-1,-1) ) ;
 
	for(int i = L ; i <= R ; i++ )
	{
		if(vis[i]) continue ;
 
		vector<int> List ;
 
		int x = i , l = i , r = i;
		while(!vis[x])
		{
			vis[x] = true ;
			List.push_back(x) ;
			
			l = min(l,x) ;
			r = max(r,x) ;
 
			x = p[x] ;
		}
 
		for(auto e : List ) intervalo[e] = make_pair(l,r) ;
 
	}
 
	vector<int> dist(n, n+5 ) ;
	priority_queue< pii , vector<pii> , greater<pii> > fila ;
 
	fila.push(make_pair(0,s)) ;
	dist[s] = 0 ;
 
	upd( intervalo[s].ff+1 , intervalo[s].ss ) ;
 
	while(!fila.empty())
	{
		int x = fila.top().ss ;
		int d = fila.top().ff ;
		fila.pop() ;
 
		if(dist[x] != d) continue ;
 
		vector<pii> adj ;
 
		if(x)
		{
			if( qry(x) >= x )
				adj.push_back(make_pair(x-1,0)) ;
			else adj.push_back(make_pair(x-1, 1)) ;
		}
		if(x+1 < n)
		{
			if( qry(x+1) >= x+1)
				adj.push_back(make_pair(x+1, 0)); 
			else adj.push_back(make_pair(x+1, 1 ) ) ;
		}
 
		for(auto e : adj)
		{
			int y = e.ff ;
			int cost = e.ss ;
 
			if(dist[y]<= cost+dist[x]) continue ;
 
			dist[y] = dist[x]+cost ;
 
			fila.push(make_pair(dist[y] , y ));
			upd( intervalo[y].ff+1, intervalo[y].ss ) ;
 
		}
 
	}
 
	ll toSum = dist[L] + dist[R] ;
	ll mx = 0 ;
 
	for(int i = L ; i <= R ; i++ )
		if(intervalo[i].ff <= s && intervalo[i].ss >= s )
			mx = max(mx, (ll)dist[i]) ;

	toSum -= mx ;
 
	return ans + 2LL*toSum ;
}
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