Submission #72964

#	Time	Username	Problem	Language	Result	Execution time	Memory
72964		Hoget157	Crayfish scrivener (IOI12_scrivener)	C++14	100 / 100	697 ms	97340 KiB

scrivener

int cnt,par[22][1000010],num[1000010];
char cs[1000010];

void Init() {
	cnt = 1;
	num[0] = -1;
}

void TypeLetter(char L) {
	cs[cnt] = L;
	par[0][cnt] = cnt - 1;
	num[cnt] = num[cnt - 1] + 1;
	for(int i = 1;i < 22;i++){
		if(par[i - 1][cnt]) par[i][cnt] = par[i - 1][par[i - 1][cnt]];
		else break;
	}
	cnt++;
}

void UndoCommands(int U) {
	for(int i = 0;i < 22;i++) par[i][cnt] = par[i][cnt - U - 1];
	cs[cnt] = cs[cnt - U - 1];
	num[cnt] = num[cnt - U - 1];
	cnt++;
}

char GetLetter(int P) {
	int tmp = cnt - 1;
	for(int i = 0;i < 22;i++){
		if(num[tmp] == P) break;
		if(((num[tmp] - P) >> i) & 1) tmp = par[i][tmp];
	}
	return cs[tmp];
}

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