Submission #1226637

#	Time	Username	Problem	Language	Result	Execution time	Memory
1226637		Malix	Ancient Books (IOI17_books)	C++20	50 / 100	198 ms	55456 KiB

books

#include "books.h"
#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> ti;
typedef vector<ll> li;
typedef vector<li> lii;
 
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))
#define all(x) (x).begin(),(x).end()
 
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;

vi a,vis,arr;

void dfs(int x){
	arr.PB(x);
	vis[x]=1;
	if(vis[a[x]]==0)dfs(a[x]);
}

long long minimum_walk(std::vector<int> p, int s) {
	a=p;
	while(a.size()&&a[a.back()]==a.back())a.pop_back();
	if(a.size()==0)return 0;
	int n=a.size();
	vis.resize(n,0);
	int pos=0;
	while(pos<n&&a[pos]==pos)pos++;
	ll ans=0;
	if(s>=n){
		ans=(s-n+1)*2LL;
		s=n-1;
	}
	if(s<pos){
		ans=(pos-s)*2LL;
		s=pos;
	}
	vector<pi> c(n,{-1,-1});
	REP(i,pos,n)if(!vis[i]&&i!=a[i]){
		arr.clear();
		dfs(i);
		sort(all(arr));
		for(auto u:arr)ans+=(ll)abs(u-a[u]);
		for(auto u:arr)c[u]={arr[0],arr.back()};
	}
	int l=s,r=s;
	queue<int> q;
	if(c[s].F!=-1)q.push(s);
	ll cnt=0;
	while(l!=pos||r!=n-1){
		while(!q.empty()){
			int x=q.front();
			q.pop();
			ans+=cnt;
			cnt=0;
			REP(i,c[x].F,l)if(c[i].F!=-1)q.push(i);
			REP(i,r+1,c[x].S)if(c[i].F!=-1)q.push(i);
			l=min(l,c[x].F);
			r=max(r,c[x].S);
		}
		if(l!=pos||r!=n-1){
			cnt+=2;
			if(l!=pos){
				l--;
				if(c[l].F!=-1)q.push(l);
			}
			if(r!=n-1){
				r++;
				if(c[r].F!=-1)q.push(r);
			}
		}
	}
	return ans+cnt*2LL;
}

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30