Submission #25864

#	Time	Username	Problem	Language	Result	Execution time	Memory
25864		akynoi	Crayfish scrivener (IOI12_scrivener)	C++14	100 / 100	746 ms	88032 KiB

scrivener

int depth[1000003];
char ch[1000003];
int pa[1000003][20];
int id[1000003];
int T, top;

void Init() { ch[T = 0] = '^'; depth[0] = -1; top = 1; }

void TypeLetter(char p) {
    depth[top] = depth[pa[top][0] = id[T++]] + 1;
    for (int i = 1; ch[pa[top][i - 1]] != '^'; i++) pa[top][i] = pa[pa[top][i - 1]][i - 1];
    ch[id[T] = top++] = p;
}

void UndoCommands(int m) { id[T + 1] = id[T - m]; T++; }

char GetLetter(int m) {
    int now = id[T], a = depth[id[T]] - m;
    for (int i = 0, p = 1; a; i++, p <<= 1)
        if (p & a) now = pa[now][i], a ^= p;
    return ch[now];
}

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