Submission #229610

#	Time	Username	Problem	Language	Result	Execution time	Memory
229610		maruii	Crayfish scrivener (IOI12_scrivener)	C++14	100 / 100	479 ms	67320 KiB

scrivener

int cnt, cnt2, par[20][1000001], A[1000001], dep[1000001];
char S[1000001];
void Init() {
}

void TypeLetter(char L) {
	++cnt2;
	S[cnt2] = L;
	dep[cnt2] = dep[A[cnt]] + 1;
	par[0][cnt2] = A[cnt];
	for (int i = 1; i < 20; ++i) par[i][cnt2] = par[i - 1][par[i - 1][cnt2]];
	++cnt;
	A[cnt] = cnt2;
}

void UndoCommands(int U) {
	int x = cnt - U;
	++cnt;
	A[cnt] = A[x];
}

char GetLetter(int P) {
	int x = A[cnt];
	for (int i = 0; i < 20; ++i) if (((dep[x] - P - 1) >> i) & 1) {
		x = par[i][x];
	}
	return S[x];
}

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