Submission #797381

#	Time	Username	Problem	Language	Result	Execution time	Memory
797381		alvingogo	Ancient Books (IOI17_books)	C++14	50 / 100	245 ms	36732 KiB

books

#include "books.h"
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define AquA cin.tie(0);ios_base::sync_with_stdio(0);
#define fs first
#define sc second
#define p_q priority_queue
using namespace std;

typedef long long ll;
struct DSU{
	vector<int> bo;
	void init(int x){
		bo.resize(x);
		iota(bo.begin(),bo.end(),0);
	}
	int find(int x){
		return bo[x]==x?x:bo[x]=find(bo[x]);
	}
	int merge(int x,int y){
		x=find(x);
		y=find(y);
		if(x==y){
			return 0;
		}
		bo[x]=y;
		return 1;
	}
}dsu;
ll minimum_walk(vector<int> p, int s) {
	ll ans=0;
	int n=p.size();
	dsu.init(n);
	vector<int> bo(n,-1),k(n),pre(n);
	for(int i=0;i<n;i++){
		if(bo[i]==-1){
			pre[i]++;
			int cnt=0;
			int f=0;
			for(int x=i;bo[x]==-1;x=p[x]){
				dsu.merge(x,i);
				bo[x]=i;
				cnt++;
				f=max(f,x);
			}
			if(cnt>=2){
				k[i]=1;
			}
			pre[f]--;
		}
		ans+=abs(i-p[i]);
	}
	for(int i=1;i<n;i++){
		pre[i]+=pre[i-1];
	}
	k[bo[s]]=1;
	for(int i=0;i+1<n;i++){
		if(pre[i]){
			dsu.merge(i,i+1);
		}
	}
	int mn=-1;
	vector<pair<int,pair<int,int> > > e;
	for(int i=0;i<n;i++){
		if(k[bo[i]]){
			if(mn!=-1){
				e.push_back({i-mn,{bo[i],bo[mn]}});
			}
			mn=i;
		}
	}
	sort(e.begin(),e.end());
	for(auto h:e){
		ans+=2*dsu.merge(h.sc.fs,h.sc.sc)*h.fs;
	}
	return ans;
}

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