Submission #1185044

#	Time	Username	Problem	Language	Result	Execution time	Memory
1185044		Gabp	Crayfish scrivener (IOI12_scrivener)	C++20	100 / 100	352 ms	140156 KiB

scrivener

#include<bits/stdc++.h>
using namespace std;

const int m = 21;

struct Node {
    char c;
    int idx;
    Node *p[m];
    
    Node(char c, Node *par) : c(c) {
        if (par) {
            idx = par->idx + 1;
            p[0] = par;
            for (int i = 1; i < m; i++) {
                p[i] = p[i - 1]->p[i - 1];
            }
        } else {
            idx = -1;
            for (int i = 0; i < m; i++) p[i] = this;
        }
    }
};

int cnt = 0;
const int N = 1e6 + 5;
Node *memo[N];

void Init() {
    memo[0] = new Node('\0', nullptr);
}

void TypeLetter(char L) {
    memo[++cnt] = new Node(L, memo[cnt]);
}

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

char GetLetter(int P) {
    int diff = memo[cnt]->idx - P;
    Node *curr = memo[cnt];
    for (int i = 0; i < m; i++) {
        if (diff & (1 << i)) curr = curr->p[i];
    }
    return curr->c;
}

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