Submission #241598

#	Time	Username	Problem	Language	Result	Execution time	Memory
241598		johutha	Crayfish scrivener (IOI12_scrivener)	C++17	100 / 100	565 ms	90616 KiB

scrivener

#include <iostream>
#include <vector>
#include <cassert>

using namespace std;

int upr[1000001][21];
char ch[1000001];
int len[1000001];
int cnt = 0;

void Init()
{
	cnt = 1;
	for (int i = 0; i < 21; i++) upr[0][i] = 0;
}

void TypeLetter(char L)
{
	ch[cnt] = L;
	len[cnt] = len[cnt - 1] + 1;
	upr[cnt][0] = cnt - 1;
	for (int i = 1; i < 21; i++) upr[cnt][i] = upr[upr[cnt][i - 1]][i - 1];
	cnt++;
}

void UndoCommands(signed U)
{
	int st = cnt - U - 1;
	ch[cnt] = ch[st];
	for (int i = 0; i < 21; i++) upr[cnt][i] = upr[st][i];
	len[cnt] = len[st];
	cnt++;
}

char GetLetter(signed P)
{
	int u = len[cnt - 1] - 1 - P;
	int c = cnt - 1;

	for (int i = 0; i < 21; i++)
	{
		if (u & (1<<i))
		{
			c = upr[c][i];
		}
	}
	return ch[c];
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 22 / 22
• Subtask 4: 26 / 26
• Subtask 5: 40 / 40