Submission #427096

#	Time	Username	Problem	Language	Result	Execution time	Memory
427096		Hazem	Ancient Books (IOI17_books)	C++14	0 / 100	2097 ms	416220 KiB

books

#include "books.h"
#include <bits/stdc++.h>
#define LL long long 

using namespace std;

const LL LINF  = 1e18;

int n;
vector<int>vec,a;
map<vector<int>,LL>mp;

bool check(){

	bool q = 1;
	for(int i=0;i<n;i++)
		q &= (a[i]==vec[i]);
	
	return q;
}

LL bt(int pos,int cur);

LL move(int pos,int cur){

	LL ret = LINF;
	if(pos<n-1)
		ret = min(ret,1+bt(pos+1,cur));
	
	if(pos>0)
		ret = min(ret,1+bt(pos-1,cur));

	return ret;
}

LL bt(int pos,int cur){

	vector<int> state = a;
	state.push_back(pos);
	state.push_back(cur);

	if(!pos&&check())
		return 0;
	
	if(mp.find(state)!=mp.end())
		return mp[state];
	
	mp[state] = LINF;

	LL ret = LINF;
	ret = min(ret,move(pos,cur));
	
	swap(cur,a[pos]);
	ret = min(ret,move(pos,cur));
	swap(cur,a[pos]);

	return mp[state] = ret;
}

long long minimum_walk(std::vector<int> P, int s) {	
	
	a = P;
	n = P.size();
	for(int i=0;i<n;i++)
		vec.push_back(i);

	return bt(0,-1);
}

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