Submission #289443

#	Time	Username	Problem	Language	Result	Execution time	Memory
289443		eohomegrownapps	Ancient Books (IOI17_books)	C++14	50 / 100	236 ms	29180 KiB

books

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

typedef long long ll;

vector<ll> cycle;
vector<int> p;
ll n;

ll minc = 1e9;
ll maxc = -1e9;

ll findcycle(ll i, ll ptr){
	cycle[i] = ptr;
	minc=min(minc,i);
	maxc=max(maxc,i);
	if (cycle[p[i]]!=-1){
		return abs(i-p[i]);
	} else {
		return abs(i-p[i]) + findcycle(p[i], ptr);
	}
}

ll minimum_walk(std::vector<int> px, int s) {
	p = px;
	n = p.size();
	cycle.resize(n,-1);

	ll cycledist = 0;
	ll ptr = 0;
	vector<ll> cyclewidth(n);
	for (ll i = 0; i<n; i++){
		if (cycle[i]!=-1){continue;}
		minc=1e9;maxc=-1e9;
		ll dist = findcycle(i,ptr);
		cyclewidth[minc]++;
		cyclewidth[maxc]--;
		cycledist+=dist;
		ptr++;
	}

	ll prev = 0;
	bool iszero = true;
	ll ctr = 0;
	for (ll i = 0; i<n; i++){
		ctr+=cyclewidth[i];
		if (iszero&&ctr>0){
			cycledist+=2*(i-prev);
			iszero = false;
		} else if ((!iszero)&&ctr==0){
			prev = i;
			iszero = true;
		}
	}
	return cycledist;
}

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