Submission #105112

#	Time	Username	Problem	Language	Result	Execution time	Memory
105112		eriksuenderhauf	Crayfish scrivener (IOI12_scrivener)	C++11	100 / 100	966 ms	129252 KiB

scrivener

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
//#include "grader.h"
using namespace std;
typedef long long int ll;
const int MAXN = 1e6 + 5;

struct node
{
	node *par[20];
	char c;
	int len = 1;
};

node *arr[MAXN];
int cnt = -1;

node *add(char x, node *cur) {
	node *ret = new node;
	if (cur != NULL)
		ret->len = cur->len + 1;
	ret->c = x;
	ret->par[0] = cur;
	for (int i = 1; i < 20; i++) {
		if (ret->par[i-1] != NULL)
			ret->par[i] = ret->par[i - 1]->par[i - 1];
		else
			break;
	}
	return ret;
}

void Init() {
}

void TypeLetter(char c) {
	cnt++;
	if (cnt == 0)
		arr[cnt] = add(c, NULL);
	else
		arr[cnt] = add(c, arr[cnt-1]);
}

void UndoCommands(int u) {
	cnt++;
	arr[cnt] = arr[cnt - u - 1];
}

char GetLetter(int k) {
	node *tmp = arr[cnt];
	k = tmp->len - k - 1;
	for (int i = 0; k != 0 && i < 20; i++) {
		if (k & 1)
			tmp = tmp->par[i];
		k /= 2;
	}
	return tmp->c;
}

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