Submission #566393

#	Time	Username	Problem	Language	Result	Execution time	Memory
566393		Siffer	Ancient Books (IOI17_books)	C++14	0 / 100	1 ms	300 KiB

books

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

#define ll long long

vector<int> v,c,vc;

int search(int n, vector<int> &p) {
	if(v[n] || p[n] == n) return 0;
	v[n] = 1;
	vc[c[n]] = 1;
	int r = 0;
	if(n > 0 && c[n-1] != c[n] && !vc[c[n-1]]) {
		int k = search(n-1, p);
		if(k) r += k + 2;
	}
	if(n+1 < p.size() && c[n+1] != c[n] && !vc[c[n+1]]) {
		int k = search(n+1, p);
		if(k) r += k + 2;
	}
	r += abs(n-p[n]);
	r += search(p[n], p);
	return r;
}

ll minimum_walk(vector<int> p, int s) {
	int n = p.size();
	c.resize(n,-1);
	v.resize(n,0);
	vc.resize(n,0);
	for(int i = 0; i < n; i++) {
		if(c[i] == -1) {
			c[i] = i;
			int k = p[i];
			while(k != i) {
				c[k] = i;
				k = p[k];
			}
		}
	}
	int r = search(s, p);
	for(int i = 1; i < n; i++) {
		if(s >= i) {
			int k = search(s-i, p);
			if(k) r += 2*i + k;
		}
		if(s+i < n) {
			int k = search(s+i, p);
			if(k) r += 2*i + k;
		}
	}
	return r;
}

Compilation message (stderr)

books.cpp: In function 'int search(int, std::vector<int>&)':
books.cpp:18:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |  if(n+1 < p.size() && c[n+1] != c[n] && !vc[c[n+1]]) {
      |     ~~~~^~~~~~~~~~

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