Submission #121976

#	Time	Username	Problem	Language	Result	Execution time	Memory
121976		nvmdava	Ancient Books (IOI17_books)	C++17	0 / 100	2 ms	384 KiB

books

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

bool in[1000005];
vector<pair<int, int> > cyc, tmp;
int mn, mx;
long long res;
void dfs(int i, vector<int>& p){
	if(in[i]) return;
	in[i] = 1;
	mx = max(mx, i);
	mn = min(mn, i);
	dfs(p[i], p);
}

long long minimum_walk(std::vector<int> p, int s) {
	for(int i = 0; i < p.size(); i++){
		res += abs(p[i] - i);
		if(in[i]) continue;
		mn = i;
		mx = i;
		dfs(i, p);
		if(mn != mx)tmp.push_back({mn , mx});
		else in[i] = 0;
	}
	if(tmp.empty()) return 0;
	int l = s, r = s;
	while(l && in[l] == 0)l--;
	while(r != p.size() && in[r] == 0) r++;
	if(l == -1) res += (r - s) * 2;
	else if(r == p.size()) res += (s - l) * 2;
	else {
		res += min(s - l, r - s) * 2;
	}
	sort(tmp.begin(), tmp.end());
	mx = -1;
	for(auto& x : tmp){
		if(mx < x.first){
			if(!cyc.empty()){
				res += 2 * (x.first - mx);
			}
			cyc.push_back(x);
		}
		mx = max(mx, x.second);
	}
	return res;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < p.size(); i++){
                 ~~^~~~~~~~~~
books.cpp:30:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(r != p.size() && in[r] == 0) r++;
        ~~^~~~~~~~~~~
books.cpp:32:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  else if(r == p.size()) res += (s - l) * 2;
          ~~^~~~~~~~~~~

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