Submission #283899

#	Time	Username	Problem	Language	Result	Execution time	Memory
283899		erd1	Ancient Books (IOI17_books)	C++14	100 / 100	911 ms	77912 KiB

books

#include "books.h"

#include<bits/stdc++.h>

using namespace std;
#define pb push_back
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
typedef pair<int, int> pii;
typedef long long lld;
typedef long double ld;

template<typename Iter>
ostream& outIt(ostream& out, Iter b, Iter e){
	for(Iter i = b; i != e; ++i)
		out << (i == b?"":" ") << *i;
	return out;
}
template<typename T1, typename T2>
ostream& operator<<(ostream& out, pair<T1, T2> p){
	return out << '(' << p.ff << ", " << p.ss << ')';
}
template<typename T>
ostream& operator<<(ostream& out, vector<T> v){
	return outIt(out << '[', all(v)) << ']';
}
vector<pii> cs;
vector<int> poss, dist, gone;
set<int> not_yet;
long long minimum_walk(vector<int> p, int s) {
	lld ans = 0;
	int pmin = INT_MAX, pmax = INT_MIN;
	for(int i = 0; i < p.size(); i++)if(p[i] != i)ans += abs(p[i]-i), cs.pb({min(i, p[i]), max(i, p[i])}), pmin = min(pmin, i), pmax = max(pmax, i);
	if(ans == 0)return 0;
	sort(all(cs));
	int r = cs.front().ff;
	gone.resize(p.size()), poss.resize(p.size()), dist.resize(p.size());
	poss[r] = 1;
	bool fl = true;
	for(int i = 0; i < cs.size(); i++){
		if(cs[i].ff > s && s > r)fl = false;
		if(cs[i].ff > r) poss[r] = poss[cs[i].ff] = 1;
		ans += 2*max(0, cs[i].ff - r);
		r = max(r, cs[i].ss);
	}
	poss[r] = 1;
	//cout << poss << endl;
	if(!fl)return ans;
	for(int i = 0; i < p.size(); i++)not_yet.insert(i);
	for(int d = 0, l = s, r = s; d < p.size(); d++, l--, r++){
		while(not_yet.lower_bound(l) != not_yet.upper_bound(r)){
			int ta = *not_yet.lower_bound(l);
			not_yet.erase(ta);
			//cout << ta << endl;
			if(poss[ta])return ans + 2*d;
			for(int x = p[ta]; not_yet.count(x); x = p[x]){
				not_yet.erase(x), l = min(l, x), r = max(r, x);
				if(poss[x])return ans + 2*d;
				//cout << x << endl;
			}
		}
	}
	assert(false);




	for(int i = 0; i < p.size(); i++)dist[i] = abs(i-s);
	//cout << dist << gone << endl;
	for(int i = 0; i < p.size(); i++){
		pii mins = {INT_MAX, -1};
		for(int j = 0; j < p.size(); j++)if(!gone[j])mins = min(mins, {dist[j], j});
		gone[mins.ss] = true;

		int ll = mins.ss, rr = p[mins.ss]; if(ll > rr)swap(ll, rr);
		for(int j = 0; j < p.size(); j++){
			dist[j] = min(dist[j], mins.ff + (ll <= j && j <= rr? 0:abs(mins.ss - j)));
		}
	}
	//for(int i = 0; i < p.size(); i++)if(p[i] == i)dist[i] *= 0;
	//cout << dist << endl;
	//return ans + 2 * (*max_element(all(dist)));
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:35:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |  for(int i = 0; i < p.size(); i++)if(p[i] != i)ans += abs(p[i]-i), cs.pb({min(i, p[i]), max(i, p[i])}), pmin = min(pmin, i), pmax = max(pmax, i);
      |                 ~~^~~~~~~~~~
books.cpp:42:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |  for(int i = 0; i < cs.size(); i++){
      |                 ~~^~~~~~~~~~~
books.cpp:51:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |  for(int i = 0; i < p.size(); i++)not_yet.insert(i);
      |                 ~~^~~~~~~~~~
books.cpp:52:33: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |  for(int d = 0, l = s, r = s; d < p.size(); d++, l--, r++){
      |                               ~~^~~~~~~~~~
books.cpp:70:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |  for(int i = 0; i < p.size(); i++)dist[i] = abs(i-s);
      |                 ~~^~~~~~~~~~
books.cpp:72:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |  for(int i = 0; i < p.size(); i++){
      |                 ~~^~~~~~~~~~
books.cpp:74:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |   for(int j = 0; j < p.size(); j++)if(!gone[j])mins = min(mins, {dist[j], j});
      |                  ~~^~~~~~~~~~
books.cpp:78:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |   for(int j = 0; j < p.size(); j++){
      |                  ~~^~~~~~~~~~

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