Submission #8086

#	Time	Username	Problem	Language	Result	Execution time	Memory
8086		dohyun0324	Crayfish scrivener (IOI12_scrivener)	C++98	34 / 100	116 ms	10552 KiB

scrivener

char last;
int p[100010][21],a[100010],pos[100010],n,len[100010];
char str[100010];
void Init() {}

void TypeLetter(char L)
{
    int i;
    n++;
    p[n][0]=pos[n-1];
    for(i=1;i<=20;i++)
    {
        p[n][i]=p[p[n][i-1]][i-1];
    }
    pos[n]=n;
    len[n]=len[p[n][0]]+1;
    str[n]=L;
}

void UndoCommands(int U)
{
    int i;
    n++;
    pos[n]=pos[n-U-1];
    len[n]=len[pos[n]];
}

char GetLetter(int P)
{
    int i;
    int m,dir=pos[n];
    m=len[n]-P-1;
    for(i=0;i<=20;i++)
    {
        if(m&(1<<i))
        {
            m-=(1<<i);
            dir=p[dir][i];
        }
    }
    return str[dir];
}

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