Submission #18849

#	Time	Username	Problem	Language	Result	Execution time	Memory
18849		suhgyuho_william	Crayfish scrivener (IOI12_scrivener)	C++98	5 / 100	299 ms	91896 KiB

scrivener

int rear,cnt;
int par[1000010][22];
int next[1000010];
char a[1000010];

void Init(){
	rear = cnt = 0;
}

void TypeLetter(char L) {
	int i;

	rear++; cnt++;
	next[cnt] = rear;
	a[rear] = L;
	par[rear][0] = next[rear-1];
	for(i=1; i<=19; i++){
		par[rear][i] = par[par[rear][i-1]][i-1];
	}
}

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

char GetLetter(int P) {
	int i,x;
	int ans;

	ans = rear;
	x = next[cnt]-(P+1);
	for(i=19; i>=0; i--){
		if(x == 0) break;
		if(x >= (1 << i)){
			x -= (1 << i);
			ans -= (1 << i);
		}
	}
	return a[ans];
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 22
• Subtask 4: 0 / 26
• Subtask 5: 0 / 40