Submission #833571

#	Time	Username	Problem	Language	Result	Execution time	Memory
833571		caganyanmaz	Ancient Books (IOI17_books)	C++17	0 / 100	8 ms	15964 KiB

books

#include <bits/stdc++.h>
#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) 
{
	ll sum = 0;
	int n = p.size();
	debug("A");
	for (int i = 0; i < n; i++)
		sum += abs(p[i] - i);
	debug("B");
	for (int i = 0; i < n; i++)
		node[i] = Node(i);
	debug("c");
	for (int i = 0; i < n; i++)
		if (node[i].head != node[p[i]].head)
			merge(node[i].head, node[p[i]].head);
	for (int i = 0; i < n; i++)
		debug(i, node[i].head);
	int counter = 0;
	for (int i = 0; i < n; i++)
		if (node[i].head == i && node[i].size > 1)
			counter++;
	debug(sum);
	debug("D");
	priority_queue<array<int, 2>> pq;
	for (int i = node[s].head; i != -1; i = node[i].nxt)
	{
		pq.push({0, i});
	}
	while (pq.size())
	{
		auto [dist, i] = pq.top();
		pq.pop();
		if (visited[i])
			continue;
		visited[i] = true;
		dist *= -1;
		if (!visited_component[node[i].head] && node[node[i].head].size > 1)
		{
			sum += 2 * dist;
			dist = 0;
			for (int j = node[i].head; j != -1; j = node[j].nxt)
				pq.push({0, j});
		}
		if (i > 0)
			pq.push({-(dist+1), i-1});
		if (i < n-1)
			pq.push({-(dist+1), i+1});
	}
	int lle = s, lri = s;
	return sum;
}

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;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:76:6: warning: unused variable 'lle' [-Wunused-variable]
   76 |  int lle = s, lri = s;
      |      ^~~
books.cpp:76:15: warning: unused variable 'lri' [-Wunused-variable]
   76 |  int lle = s, lri = s;
      |               ^~~

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