Submission #230810

#	Time	Username	Problem	Language	Result	Execution time	Memory
230810		arbor	Crayfish scrivener (IOI12_scrivener)	C++14	34 / 100	481 ms	62680 KiB

scrivener

#include <bits/stdc++.h>

#define all(x) x.begin(), x.end()
#define lc (i << 1)
#define rc (i << 1 | 1)
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const int MN = 1e6 + 5, LN = 17, MOD = 1e9 + 7, INF = 0x3f3f3f3f, BSZ = 320;
char s[MN];
int spt[MN][21], dep[MN];
int cur;

void Init() {

}

// simiulate it as a tree, append on to previous node
void TypeLetter(char L) {
    cur++;
    s[cur] = L;
    spt[cur][0] = cur - 1;
    dep[cur] = dep[cur - 1] + 1;
    for (int j = 1; j < LN; j++)
        spt[cur][j] = spt[spt[cur][j - 1]][j - 1];
}

// undo will also act as an append, we go back U additions (therefore including all the undos as well)
// we can delete everything in the subtree by readding it to its parent
void UndoCommands(int U) {
    int last = cur - U;
    cur++;
    s[cur] = s[last];
    int par = spt[last][0];
    spt[cur][0] = par;
    dep[cur] = dep[par] + 1;
    for (int j = 1; j < LN; j++)
        spt[cur][j] = spt[spt[cur][j - 1]][j - 1];
}

char GetLetter(int P) {
    P++;
    int dis = dep[cur] - P;
    int now = cur;
    for (int j = LN - 1; j >= 0; j--)
        if (dis - (1 << j) >= 0) {
            now = spt[now][j];
            dis -= (1 << j);
        }
    return s[now];
}

/*
int main() {
    Init();
    TypeLetter('a');
    TypeLetter('b');
    cout << GetLetter(1) << '\n';
    TypeLetter('d');
    UndoCommands(2);
    UndoCommands(1);
    cout << GetLetter(2) << '\n';
    TypeLetter('e');
    UndoCommands(1);
    UndoCommands(5);
    TypeLetter('c');
    cout << GetLetter(2) << '\n';
    UndoCommands(2) ;
    cout << GetLetter(2) << '\n';
}
 */

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