Submission #481162

#	Time	Username	Problem	Language	Result	Execution time	Memory
481162		glome	Arranging Shoes (IOI19_shoes)	C++17	65 / 100	810 ms	3120 KiB

shoes

#include "shoes.h"

#include<bits/stdc++.h>

using namespace std;

bool check(vector<int> s) {
	for (int i = 0; i<s.size(); i+=2) {
		if(s[i] > 0 || -s[i] != s[i+1]) {
			return 0;
		}
	}
	return 1;
}

long long count_swaps(std::vector<int> s) {
	int n = s.size() / 2;
	if(s.size() <= 20000) {
		long long ans = 0;
		while(!check(s)) {
			vector<int> news;
			for (int i = 0; i<s.size(); i+=2) {
				if(-s[i] == s[i + 1] && s[i] < 0) {
					continue;
				}
				if(s[i] < 0) {
					for (int j = i + 1; j<s.size(); j++) {
						if(s[j] == -s[i]) {
							ans += abs((i + 1) - j);
							for (int k = 0; k<s.size(); k++) {
								if(k == j) {
									continue;
								}
								if(k == i + 1) {
									news.push_back(s[j]);
								}
								news.push_back(s[k]);
							}
							break;
						}
					}
				}
				else {
					for (int j = i + 1; j<s.size(); j++) {
						if(s[j] == -s[i]) {
							ans += abs(i - j);
							for (int k = 0; k<s.size(); k++) {
								if(k == j) {
									continue;
								}
								if(k == i) {
									news.push_back(s[j]);
								}
								news.push_back(s[k]);
							}
							break;
						}
					}
				}	
				break;
			}
			s = news;
		}
		return ans;
	}
	bool ok = 1;
	for (int i = 0; i<s.size() / 2; i++) {
		if(-s[i] == s[i+n] && s[i] < 0) {

		}
		else {
			ok = 0;
		}
	}
	if(ok) {
		return (long long) n * (long long) (n - 1) / 2; 
	}
	map<int, unordered_set<int>> neg, pos;
	for (int i = 0; i<s.size(); i++) {
		if(i < 0) {
			neg[s[i]].insert(i);
		}
		else {
			pos[s[i]].insert(i);
		}
	}
	long long ans = 0;
	for (int i = 0; i<s.size(); i++) {
		if(-s[i] == s[i+1]) {
			i++;
			continue;
		}

	}
	return ans;	
}

Compilation message (stderr)

shoes.cpp: In function 'bool check(std::vector<int>)':
shoes.cpp:8:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    8 |  for (int i = 0; i<s.size(); i+=2) {
      |                  ~^~~~~~~~~
shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:22:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |    for (int i = 0; i<s.size(); i+=2) {
      |                    ~^~~~~~~~~
shoes.cpp:27:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |      for (int j = i + 1; j<s.size(); j++) {
      |                          ~^~~~~~~~~
shoes.cpp:30:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |        for (int k = 0; k<s.size(); k++) {
      |                        ~^~~~~~~~~
shoes.cpp:44:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |      for (int j = i + 1; j<s.size(); j++) {
      |                          ~^~~~~~~~~
shoes.cpp:47:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |        for (int k = 0; k<s.size(); k++) {
      |                        ~^~~~~~~~~
shoes.cpp:67:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |  for (int i = 0; i<s.size() / 2; i++) {
      |                  ~^~~~~~~~~~~~~
shoes.cpp:79:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |  for (int i = 0; i<s.size(); i++) {
      |                  ~^~~~~~~~~
shoes.cpp:88:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   88 |  for (int i = 0; i<s.size(); i++) {
      |                  ~^~~~~~~~~

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