Submission #40165

#	Time	Username	Problem	Language	Result	Execution time	Memory
40165		alenam0161	Ancient Books (IOI17_books)	C++14	12 / 100	0 ms	3976 KiB

books

#include "books.h"
#include <iostream>
#include <algorithm>
using namespace std;
const int N = 1e6 + 7;
bool used[N];
vector<int> cycl,a;
long long ans;
void dfs(int v) {
	used[v] = true;
	cycl.push_back(v);
	ans += abs(a[v] - v);
	if (used[a[v]])return;
	dfs(a[v]);
}
void print(vector<int> v) {
	for (int to : v) {
		cout << to << " :";
	}
	cout << endl;
}
bool us[N];
long long minimum_walk(std::vector<int> p, int s) {
	a = p;
	int n = p.size();
	vector<pair<long long,int>> ms;
	vector<pair<int,int>> art;
	int lst = n - 1;
	while (lst >= 0 && p[lst] == lst)lst--;
	for (int i = 0; i < n; ++i) {
		if (used[i])continue;
		ans = 0;
		cycl.clear();
		dfs(i);
		if (ans > 0) {
			ms.push_back({ ans,i });
			sort(cycl.begin(), cycl.end());
			art.push_back({ cycl[0],cycl.back() });
		}
	}
	while (ms.size() > 0 && ms.back().first == 0)ms.pop_back();
	if (ms.size() == 0)return 0ll;
	long long an = 0;
	for (int i = 0; i < ms.size(); ++i) {
		an += ms[i].first;// cout << ms[i].first << " " << ms[i].second << endl;
	}
	an += ms.back().second * 2ll;
	for (int i = 0; i+1 < art.size(); ++i) {
		int q = 0;
		an -= (art[i + 1].first - art[i].first) * 2;
	}
	return an;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:44:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < ms.size(); ++i) {
                    ^
books.cpp:48:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i+1 < art.size(); ++i) {
                      ^
books.cpp:49:7: warning: unused variable 'q' [-Wunused-variable]
   int q = 0;
       ^

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