Submission #1061739

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061739		fv3	Ancient Books (IOI17_books)	C++14	12 / 100	1 ms	348 KiB

books

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

using namespace std;
typedef long long ll;

int N, S;
vector<int> P;

ll res = 0;

int l, r;
void trim_edges()
{
	while (P[l] == l && l < N)
		l++;
	while (P[r] == r && r >= 0)
		r--;
}

int cur = 0;
int go_right(int index)
{
	for (int i = index; i < r; i++)
	{
		if (P[i] > cur)
			swap(P[i], cur);
	}
	swap(cur, P[r]);

	res += r - index;
	index = r;
	trim_edges();

	return index;
}

int go_left(int index)
{
	res += index - r;
	index = r;
	while (cur == r && r > 0)
		swap(cur, P[r--]);

	int pos = r;
	for (; P[pos] != r; pos--)
	{
		if (cur > P[pos])
			swap(P[pos], cur);
	}

	res += index - pos;
	trim_edges();

	return pos;
}

ll minimum_walk(vector<int> p_, int s_) 
{
	P = p_;	S = s_;
	N = P.size();	

	l = 0, r = N - 1;
	trim_edges();
	if (l == N) return 0;

	res = l;

	int index = l;
	for (int t = 0; l <= r; t++)
	{
		if ((t&1) == 0)
			index = go_right(index);
		else
			index = go_left(index);
	}
	res += index;
	return res;
}

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