Submission #98932

#	Time	Username	Problem	Language	Result	Execution time	Memory
98932		square1001	Ancient Books (IOI17_books)	C++14	0 / 100	3 ms	384 KiB

books

#include "books.h"
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
const long long inf = 1LL << 61;
long long minimum_walk(std::vector<int> p, int s) {
	int n = p.size();
	vector<pair<long long, long long> > cycles;
	vector<bool> vis(n);
	long long off = 0;
	for(int i = 0; i < n; ++i) {
		if(vis[i]) continue;
		long long cl = -inf, cr = inf;
		int pos = i;
		while(!vis[pos]) {
			if(pos <= s) cl = max(cl, (long long)pos);
			if(pos >= s) cr = min(cr, (long long)pos);
			vis[pos] = true;
			off += abs(p[pos] - pos);
			pos = p[pos];
		}
		if(p[i] == i) continue;
		cycles.push_back(make_pair(cl - s, cr - s));
	}
	sort(cycles.begin(), cycles.end());
	/*
	for(pair<long long, long long> i : cycles) {
		cout << i.first << ' ' << i.second << endl;
	}
	* */
	long long ans = inf, cur = 0;
	for(int i = 0; i <= cycles.size(); ++i) {
		ans = min(ans, (i != cycles.size() ? -cycles[i].first : 0) * 2 + cur * 2);
		if(i != cycles.size()) cur = max(cur, cycles[i].second);
	}
	return ans + off;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:33:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i <= cycles.size(); ++i) {
                 ~~^~~~~~~~~~~~~~~~
books.cpp:34:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   ans = min(ans, (i != cycles.size() ? -cycles[i].first : 0) * 2 + cur * 2);
                   ~~^~~~~~~~~~~~~~~~
books.cpp:35:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(i != cycles.size()) cur = max(cur, cycles[i].second);
      ~~^~~~~~~~~~~~~~~~

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