Submission #423599

#	Time	Username	Problem	Language	Result	Execution time	Memory
423599		schse	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	382 ms	277180 KiB

shoes

#include "shoes.h"
#ifndef EVAL
#include "grader.cpp"
#endif
#include <bits/stdc++.h>
using namespace std;

struct segtree
{
	int N;
	vector<int> tree;
	int upd(int index, int b, int e, int l, int r)
	{
		if (l <= b && e <= r)
			return ++tree[index];
		if (r <= b || e <= l)
			return tree[index];
		return upd(index * 2, b, (e + b) / 2, l, r) +
			   upd(index * 2 + 1, (e + b) / 2, e, l, r);
	}
	void upd(int l, int r)
	{
		upd(1, 0, N, l, r);
	}

	int query(int index, int b, int e, int pos, int cary)
	{
		tree[index] += cary;
		if (pos < b || e <= pos)
			return 0;
		if (e - b == 1)
			return tree[index];
		int r = query(index * 2, b, (e + b) / 2, pos, tree[index]) +
				query(index * 2 + 1, (e + b) / 2, e, pos, tree[index]);
		tree[index] = 0;
		return r;
	}

	int query(int pos)
	{
		int r = query(1, 0, N, pos, 0);
		return r;
	}

} tree;

long long count_swaps(std::vector<int> s)
{
	tree.N = s.size();
	tree.tree.resize(tree.N * 4 + 5, 0);
	vector<int> posadd(s.size());
	vector<bool> sorted(s.size(), false);
	vector<queue<int>> pleft(s.size() + 1), pright(s.size() + 1);
	iota(posadd.begin(), posadd.end(), 0);

	long long numswaps = 0;

	for (int i = 0; i < s.size(); i++)
		(s[i] > 0 ? pright : pleft)[abs(s[i])].push(i);

	for (int i = 1; i < s.size(); i++)
		tree.upd(i, s.size());


	for (int e, i = 0; i < s.size(); i++)
	{
		if (sorted[i])
			continue;
		(s[i] > 0 ? pright : pleft)[abs(s[i])].pop();

		e = (s[i] < 0 ? pright : pleft)[abs(s[i])].front();
		(s[i] < 0 ? pright : pleft)[abs(s[i])].pop();

		sorted[i] = sorted[e] = true;

		tree.upd(i + 1, e);
		numswaps += tree.query(e) - tree.query(i) - 1;

		if (s[i] > 0)
			numswaps++;
	}

	return numswaps;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:58:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |  for (int i = 0; i < s.size(); i++)
      |                  ~~^~~~~~~~~~
shoes.cpp:61:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |  for (int i = 1; i < s.size(); i++)
      |                  ~~^~~~~~~~~~
shoes.cpp:65:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |  for (int e, i = 0; i < s.size(); i++)
      |                     ~~^~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 15 / 15