Submission #74369

#	Time	Username	Problem	Language	Result	Execution time	Memory
74369		nvmdava	Ancient Books (IOI17_books)	C++17	50 / 100	206 ms	13292 KiB

books

#include "books.h"
#include <bits/stdc++.h>
using namespace std;
int r = -1, l = 1000001;
vector<int> p;
bool in[1000001];
int cl = -1;
int s;
int cr = 1000001;
void go(int v){
	if(in[v] == 1){
		return;
	}
	if(v <= s){
		cl = max(cl, v);
	} else {
		cr = min(cr, v);
	}
	in[v] = 1;
	r = max(r, v);
	go(p[v]);
}
 
long long minimum_walk(vector<int> p, int s) {
	::p = p;
	::s = s;
	int q = 0;
	long long ans = 0;
	for(int i = 0; i < p.size(); i++){
		ans += (long long)abs(i - p[i]);
		if(in[i] || p[i] == i) continue;
		l = min(l, i);
		if(r < i && r != -1){
			ans += (long long)(i - r) * 2;
		}
		go(i);
	}
	if(s < l && l != 1000001){
		ans += (l - s) * 2;
	} else if(s > r &&r != -1){
		ans += (r - s) * 2;
	}else if(cl != -1 && cr != 1000001) ans +=2 *  min(s - cl, cr - s);
	else if(cl != -1) ans += 2 * (s - cl);
	else if(cr != 1000001) ans += 2 * (cr - s);
	return ans;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:29:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < p.size(); i++){
                 ~~^~~~~~~~~~
books.cpp:27:6: warning: unused variable 'q' [-Wunused-variable]
  int q = 0;
      ^

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