Submission #833716

#	Time	Username	Problem	Language	Result	Execution time	Memory
833716		caganyanmaz	Ancient Books (IOI17_books)	C++17	50 / 100	120 ms	35084 KiB

books

#include <bits/stdc++.h>
#define pb push_back
#include "books.h"
#define ll long long 
using namespace std;

//#define DEBUGGING
#ifdef DEBUGGING
#include "../debug.h"
#else
#define debug(x...) void(42)
#endif

struct Node
{
	int head, tail, size, nxt;
	Node(int i) : head(i), tail(i), size(1), nxt(-1) {}
	Node() : Node(-1) {}

};

constexpr static int MXN = 1e6;
Node node[MXN];
bitset<MXN> visited;
bitset<MXN> visited_component;

void merge(int a, int b);

ll minimum_walk(vector<int> p, int s) 
{
	int n = p.size();

	vector<int> rp(n);
	for (int i = 0; i < n; i++)
		rp[p[i]] = i;
	vector<int> v;
	ll sum = 0;
	int current = 0;
	vector<int> possibilities;
	int spos = MXN;
	int epos = -1;

	for (int i = 0; i < n-1; i++)
	{

		if (p[i] > i)
			current++;
		if (rp[i] < i)
			current--;
		if (current > 0)
		{
			spos = min(spos, i);
			epos = max(epos, i+1);
		}
		debug(current, i);
		sum += current * 2;
		v.pb(current);
	}
	if (sum == 0)
		return sum;
	possibilities.pb(spos);

	for (int i = spos; i < epos; i++)
	{
		if (v[i] == 0)
		{
			if (i > 0 && v[i-1] > 0)
				possibilities.pb(i);
			if (i < n-2 && v[i+1] > 0)
				possibilities.pb(i+1);
			sum += 2;
		}
	}
	possibilities.pb(epos);
	debug(spos, epos, sum);

	ll first_cost = MXN;
	for (int i : possibilities)
		first_cost = min<ll>(first_cost, abs(s - i));

	return sum + first_cost * 2;


}

void merge(int a, int b)
{
	if (node[a].size < node[b].size) swap(a, b);
	node[a].size += node[b].size;
	node[node[a].tail].nxt = b;
	node[a].tail = node[b].tail;
	for (;b!=-1;b=node[b].nxt)
		node[b].head = a;
}

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