Submission #542850

#	Time	Username	Problem	Language	Result	Execution time	Memory
542850		zggf	Ancient Books (IOI17_books)	C++14	100 / 100	208 ms	42448 KiB

books

#include "books.h"
#define f first
#define s second
#include <bits/stdc++.h>

using namespace std;

vector<pair<int, int>> tab;

void solve(int a, int b, int &na, int &nb){
	//cout<<a<<" "<<b<<" "<<na<<" "<<nb<<'\n';
	int ta = na;
	int tb = nb;

	for(int i = na; i <= a; i++){
		if(tab[i].f!=-1){
			ta = min(ta, tab[i].f);
			tb = max(tb, tab[i].s);
			//cout<<i<<" "<<tab[i].f<<" "<<tab[i].s<<'\n';
		}
	}
	for(int i = b; i <= nb; i++){
		if(tab[i].f!=-1){
			ta = min(ta, tab[i].f);
			tb = max(tb, tab[i].s);
			//cout<<i<<" "<<tab[i].f<<" "<<tab[i].s<<'\n';
		}
	}
	if(ta!=na||nb!=tb) solve(na-1, nb+1, ta, tb);
	na = ta;
	nb = tb;
}

long long minimum_walk(std::vector<int> p, int s) {
	int n = p.size();
	vector<int> odw(n);
	long long wyn = 0;
	vector<pair<int, int>> inp;
	vector<pair<int, int>> inp2;
	tab.resize(n, {-1, -1});
	int globMax=-1e9, globMin=1e9;
	for(int i = 0; i < n; i++){
		int pt = i;
		if(!odw[pt]){
			if(p[pt]!=pt){
				int mini = 1e9;
				int maxi = -1e9;
				vector<int> stck;
				while(!odw[pt]){
					stck.push_back(pt);
					mini = min(mini, pt);
					maxi = max(maxi, pt);
					odw[pt] = true;
					wyn+=abs(p[pt]-pt);
					pt = p[pt];	
				}
				globMax = max(globMax, maxi);
				globMin = min(globMin, mini);
				for(auto it:stck) tab[it] = {mini, maxi};
				inp2.push_back({mini, -i});
				inp2.push_back({maxi, i});
				inp.push_back({mini, maxi});
			}else{
				tab[i] = {-1, -1};
			       	odw[pt] = true;
			}
		}
	}
	inp.push_back({s, s});
	sort(inp.begin(), inp.end());
	int dal = -1;
	int cA=-1, cB=-1;
	bool bylo = false;
	for(int i = 0; i < inp.size(); i++){
		while(dal>inp[i].f){
			dal = max(dal, inp[i].s);
			i++;	
			if(i>=inp.size()) break;
		}
		if(dal>=s){
			cB = dal;
			bylo = true;
		}
		if(i<inp.size()){
			if(i!=0) wyn+=2*(inp[i].f-dal);
			dal = inp[i].s;
		}
		if(!bylo) cA=inp[i].f;
	}
	int pocz=s, kon=s;
	//cout<<cA<<" "<<cB<<'\n';
	while(true){
		//cout<<pocz<<" "<<kon<<'\n';
		solve(pocz, kon, pocz, kon);
		//cout<<pocz<<" "<<kon<<'\n';
		if(pocz>cA&&kon<cB){
			wyn+=2;
			pocz--;
			kon++;
		}else break;
	}
	return wyn;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:74:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |  for(int i = 0; i < inp.size(); i++){
      |                 ~~^~~~~~~~~~~~
books.cpp:78:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |    if(i>=inp.size()) break;
      |       ~^~~~~~~~~~~~
books.cpp:84:7: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   84 |   if(i<inp.size()){
      |      ~^~~~~~~~~~~

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