Submission #465696

#	Time	Username	Problem	Language	Result	Execution time	Memory
465696		tomsyd	Arranging Shoes (IOI19_shoes)	C++17	10 / 100	1084 ms	5396 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;

bool ok(vector<int>& s){
	for (int i=1; i<s.size(); i += 2){
		if (s[i-1] < 0 and -s[i-1] == s[i]){
			continue;
		}
		return false;
	}
	return true;
}

long long count_swaps(vector<int> s) {
	vector<pair<int,int>> v;
	for (int i=1; i<s.size(); ++i){
		v.emplace_back(i-1,i);
	}
	int ans = 1e9;
	if (ok(s)) ans = 0;
	do{
		vector<int> cp = s;
		int cnt = 0;
		for (auto j:v){
			swap(cp[j.first],cp[j.second]);
			++cnt;
			if (ok(cp)) break;
		}
		ans = min(ans,cnt);
	} while (next_permutation(v.begin(),v.end()));
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'bool ok(std::vector<int>&)':
shoes.cpp:6:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    6 |  for (int i=1; i<s.size(); i += 2){
      |                ~^~~~~~~~~
shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:17:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |  for (int i=1; i<s.size(); ++i){
      |                ~^~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15